CA1338179C - Canine biscuits containing an inorganic pyrophosphate - Google Patents

Abstract

This invention relates to dry animal biscuits and raw hide containing pyrophosphate and the process for preparing same, which will prevent the accumulation of tartar on the teeth of dogs. The dog biscuit and raw hide may have a coating containing at least one pyrophosphate and the invention also relates to the process for preparing dry animal biscuits with a coating containing at least one pyrophosphate.

Description

CANINE BISCUITS
CONTAINING AN INORGANIC PYROPHOSPHATE
BROAD DESCRIPTION OF THE INVENTION
An ob~ect of the lnventlon ls to provlde dry animal biscuits containing pyrophosphate, partlcularly dog blscuits contalnlng pyrophosphate. Another obiect of the lnventlon ls to provlde a process for preparlng dog blscults contalning pyrophosphate. Another ob~ect of the invention is to provide a process for the prevention of tartar accumulation on the teeth of dogs. A further ob~ect of the invention is to pro-vide a process for the prevention of tartar accumulation on the teeth of dogs by the chewing and eating of dog biscuits contalning pyrophosphate by the dogs.
An ob~ect of the invention is to provide nutritionally-balanced dry biscuits contalnlng pyrophosphate.
Another ob~ect of the invention is to provide a process for preparing nutritionally-balanced dog biscults containing pyro-phosphate. Another ob~ect of the inventlon is to provide a process for the prevention of tartar accumulation on the teeth of dogs. A further ob~ect of the inventlon ls to provlde a process for the prevention of tartar accumulation on the teeth of dogs by the chewlng and eating of nutrltlonally-balanced dog biscuits contalning pyrophosphate by the dogs.
An ob~ect of the lnvention is to provlde dog blscuits having a coating contalnlng at least one pyrophosphate.
Another ob~ect of the lnventlon ls to provlde a process for preparlng dog blscults, havlng a coatlng containing at least one pyrophosphate. Another ob~ect of the lnventlon ls to a~

~ 73783-60 .

provlde a process for the preventlon of tartar accumulatlon on the teeth of dogs. A further ob~ect of the lnvention ls to provide a process for the preventlon of tartar accumulation on the teeth of dogs by the chewlng and eatlng of dog blscults having a coatlng containlng at least one pyrophosphate by the dogs.
An ob~ect of the lnventlon ls to provlde raw hlde contalnlng pyrophosphate, partlcularly ln strlp form. Another ob~ect of the lnventlon ls to provlde a process for preparlng raw hlde, partlcularly ln strip form, contalnlng pyrophos-phate. Another ob~ect of the lnventlon ls to provlde a process for the preventlon of tartar accumulatlon on the teeth of dogs. A further object of the lnventlon ls to provlde a pro-cess for the preventlon of tartar accumulatlon on the teeth of dogs by the chewlng and eatlng of raw hlde contalnlng pyro-phosphate, partlcularly ln strlp form, by the dogs.
An ob~ect of the lnvention ls to provlde raw hlde havlng a coatlng contalnlng pyrophosphate, partlcularly ln strlp form. Another ob~ect of the lnventlon ls to provlde a process for preparlng raw hlde, partlcularly ln strlp form, havlng a coatlng contalnlng pyrophosphate. Another ob~ect of the inventlon ls to provlde a process for the preventlon of tartar accumulatlon on the teeth of dogs. A further ob~ect of the lnventlon ls to provide a process for the preventlon of tartar accumulatlon on the teeth of dogs by the chewlng and eatlng of raw hlde, partlcularly ln strlp form, havlng a coatlng containlng pyrophosphate by the dogs. Another ob~ect ls to provlde a coatlng for human or animal baked dough prod-ucts.

An object of the invention is to provide devices, compositions and the like containing pyrophosphate. A further object of the invention is to provide processes for the prevention or reduction of tartar accumulation on the teeth of dogs by such devices, compositions and the like. Other objects and advantages of the invention are set out herein or are obvious herefrom to one skilled in the art.
The objects and advantages of the invention are achieved by the compositions, processes, devices, etc., of the invention.
The invention involves a process for preparing dog biscuit dough which contains at least one inorganic pyrophosphate. The process includes admixing the ingredients of the biscuit dough and the at least one inorganic pyrophosphate. The inorganic pyrophosphate also reduces the accumulation of tartar on the teeth of dogs.
Tartar is an incrustation of the teeth consisting of salivary secretion, food residue and various salts, such as, calcium carbonate or phosphate. Tartar is also termed dental calculus.
Caries are cavities or decay of the teeth which begins at the surface of the tooth and may progress through the dentine into the pulp cavity. It is believed that the action of microorganisms in the mouth on ingested sugars and carbohydrates produces acids that eat away the enamel. By preventing the formation of calculus or tartar, the invention formulation is in effect an anti-cariogenic agent.

13~817~

This invention relates to baked dog food comprising a soft center portion and an outer portion, the center portion comprising at least one alkali metal inorganic pyrophosphate, the center portion being softer than the outer portion, the center portion containing about 0.1 to about 10 weight percent of said at least one alkali metal inorganic pyrophosphate, based upon the total weight of the baked dog food, said at least one alkali metal inorganic pyrophosphate being water soluble, the baked dog food being slightly acidic to neutral, the baked dog food having a water activity of 0.70 or less, and the baked dog food containing 15 weight percent or less, based upon the total weight of the baked dog food, of water.
This invention further provides a process for making a baked blscuit for the prevention of tartar accumulation on the teeth of a dog or a cat, by chewing or eating by the dog or cat of a tartar inhibiting amount of at least one baked dog biscuit or baked cat biscuit, respectively, the process comprising forming a dough by admixing ingredients comprising flour, water, and an effective antitartar amount of at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.5 to about 3.5 weight percent, based on the total weight of the at least one baked dog biscuit or baked cat biscuit containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal pyrophosphate being water soluble, forming the dough into pieces, and baking the pieces, the at least one baked dog biscuit or baked cat biscuit containing at least one alkali metal inorganic pyrophosphate being slightly acid to near neutral, the at least one baked dog biscuit or baked cat biscuit having a water activity of 0.70 or less, and the at least one baked dog biscuit or baked cat biscuit containing about 5 to about 15 weight percent, based on the total weight of the at least one baked dog biscuit or baked cat biscuit, of water.
The invention also relates to a process for making raw hide for the prevention of tartar accumulation on the teeth of a dog, by chewing or eating by the dog of a tartar inhibiting amount of raw hide, the process comprising coating raw hide with an edible coating comprising an effective antitartar amount of at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.1 to about 5 weight percent, based on the total weight of the raw hide containing at least one alkali metal inorganic pyrophosphate, of P207, said at least one alkali metal inorganic pyrophosphate being water soluble, and drying the coating, the raw hide containing an edible coating containing at least one alkali metal inorganic pyrophosphate being slightly acid to near neutral, and the raw hide containing an edible coating containing at least one alkali metal inorganic pyrophosphate being chewable, tough and flexible.
The invention also provides a process for making pet foods for the prevention of tartar accumulation on the teeth of a dentulous animal, by chewing or eating by the animal of a tartar inhibiting amount of animal food, the process comprlsing coating an animal food with an effective antitartar amount of at least one 3b 13~8179 alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.1 to about 5 weight percent, based on the total weight of the animal food containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal inorganic pyrophosphate being water soluble.
As well, the invention provides a baked dog or cat biscuit which comprises a tartar-reduction effective amount of at least one metal inorganic phosphate of the formula Mn+2PnO3n+1, wherein M is a univalent metal and n is 2, 3, 4 or 5, or of the formula M'nPnO3n+1, where M' is a divalent metal and n has the above meaning, said at least one metal phosphate having an oxide ratio of cationic oxides (M2O or M'O) and anionic oxides (P205) being between 1 and 2 or being 2.

Preferably the dry dough lngredients and the inor-ganic pyrophosphate salts are mixed, then water is added and the mixing continued, and finally the fat (tallow) is added and thoroughly mixed in.
The dog biscuits can be made from any suitable dough.
In one advantageous embodiment, a bone-shaped canine biscuit is provided which is baked from a dough comprising wheat flour, wheat meal, soybean meal, meat and bone meals, animal fat and water.
The dog biscuit dough preferably contalns about 0.1 to about 10 weight percent of the at least one lnorganlc pyrophosphate compound, and most preferably about 0.5 to about 5 weight percent of said at least one inorganic pyrophosphate compound. The preferred lnorganlc pyrophosphate salt(s) ls an alkali metal pyrophosphate. While the preferred alkali metal pyrophosphate is tetrasodium pyrophosphate, most preferably the dog biscuit dough contains a combination of sodium acid pyrophosphate and tetrapotassium pyrophosphate (or tetrasodium pyrophosphate).
The invention also involves a process for preparing unbaked dog biscuits from the dog biscuit dough. The inven-tion also involves unbaked dog biscuits which contain at least one inorganic pyrophosphate. The dog blscuit pieces preferab-ly are bone shaped. The unbaked dog biscuits preferably have a moisture content usually in the range of about 25 to about 40 weight percent, preferably about 33 to about 35 weight percent.

13~817g The invention also involves a process for preparing baked dog biscuits which contain at least one inorganic pyrophosphate. The process includes:
(a) shaping a dog biscuit dough, which contains the at least one inorganic pyrophosphate, into dog biscuit pieces comprising unbaked dog biscuits; and (b) baking the unbaked dog biscuits.
The baked dog biscuits can be dried, if necessary, to obtain the desired moisture level. The baked dog biscuits should have a moisture content of 13 weight percent or less, advantageously between about 5 and 13 weight percent, preferably between about 8 and about 12 weight percent.
The invention product is baked so that it comprises a baked dog biscuit which contains at least one inorganic pyrophosphate.
The invention further involves baked dog biscuits which contain at least one inorganic pyrophosphate. The ingredients, ratios, ranges, etc., for the invention dog biscuit dough applies to the invention baked dog biscuits, except as otherwise noted herein.
The invention product preferably should be slightly acid to neutral.
The inorganic pyrophosphates are anti-tartar, anti-plaque or anti-calculus agents. The invention product exhibits anti-tartar properties over its normal shelf life. The invention product does not adversely affect canine tooth enamel.
The invention further involves a process for the prevention or reduction of tartar accumulation on the teeth of 133817~
dogs. The process lncludes the chewlng and/or eating of the lnventlon baked dog blscults by the dogs. (The term "dog biscult" hereln means a baked dog biscuit unless otherwlse stated hereln or otherwise obvious herefrom to one skllled ln the art.) The lnventlon biscuits, when eaten and chewed by dogs, cleans tooth surfaces, removes tartar (by mechanical action~, and exercises and massages the gums. The pyrophos-phate ln the lnvention blscuits prevents or reduces the forma-tlon of tartar on the dog's teeth. The pyrophosphate, ln thelevels lnvolved, does not adversely affect the gastrolntestin-al system or the health of the dogs.
As used hereln, all parts, percentages, ratlos and proportlons are on a welght basis unless otherwlse stated hereln or otherwlse obvious herefrom to one skilled in the art. As used hereln, all temperatures are in degrees Fahren-heit unless otherwlse stated hereln or otherwlse obvlous herefrom to one skilled in the art.
Dental calculus, or tartar as it ls sometlmes called, is a deposit which forms on the surfaces of the teeth at the gingival margin. Supraglnglval calculus appears principally ln the areas near the orifices of the salivary ducts; e.g., on the llngual surfaces of the lower anterlor teeth and on the buccal surfaces of the upper first and second molars, and on the dlstal surfaces of the posterlor molars. Mature calculus consists of an inorganic portion which is largely calclum phosphate arranged ln a hydroxylapatlte crystal lattlce struc-ture slmilar to one, enamel and dentine. An organic portion is also present and consists of desguamated epithelial cells, leukocytes, salivary sediment, food debris and varlous types of microorganlsms. As the mature calculus develops, it becomes visibly whlte or yellowlsh in color unless stained or discolored by some extraneous agency. In addition to being unsightly and undesirable from an aesthetlc standpoint, the mature calculus deposits are constant sources of irritatlon of the ginglva and thereby are a contributlng factor to glngivl-tls and other diseases of the supporting structures of the teeth, the irrltation decreasing the reslstance of tlssues to endogenous and exogenous organlsms.
The dog biscuits containing pyrophosphate can be made from any suitable dough.
Any suitable dough comprising at least one flour, meal, fat and water can be employed for the product. For instance, when the desired product is a canine biscuit, a conventional dough for dog biscults can be used, optionally containlng discrete particles of meat and/or meat byproducts or farinaceous material. Such doughs typically contain fat solids. Examples of suitable doughs for the production of hard dog biscuits are dlsclosed in U.S. Patent No. 4,454,163, and suitable doughs for the production of soft dog biscuits Icontaining humectant to control water activlty) are dlsclosed ln U.S. Patent No. 4,454,164. Partlculate protelnaceous particles, such as, particles of meat, texturized vegetable protein and/or meat byproducts, can be lncorporated to add flavor to the blscuits and texturize the surface. Particulate farlnaceous materlals, such as, bran partlcles, can also be 13:~8179 employed to texturize the interior and/or surface of the blscults and to provlde other useful propertles to the prod-uct. A dough found to produce blscuits highly palatable to dogs lncludes suitable proportlons of wheat flour, wheat meal, soybean meal, meat and bone meal, anlmal fat and natural flavors ln admlxture wlth water. The meal used ln the doughs sultable for productlon of blscults useful ln the lnventlon can comprlse meat and/or bone and/or vegetable matter lnclud-lng farlnaceous materlals, materlals prepared from legumes such as beans and peas, tuberous materlals such as potato meal, and the llke. The meals can be flnely or coarsely ground as deslred for the texture. Flours made from any sultable farlnaceous materlal can be used.
The doughs generally have a water actlvlty of about 0.90 and above upon completion of mixing of the dough ingredl-ents. A sultable dough contalns farlnaceous materlal, an edlble oll, an antloxidant, an antimycotic, salt, animal fat, added vltamlns and minerals, such as those dlsclosed ln U.S.
Patent No. 4,229,485, column 5, llnes 7 to 57. The composl-tlons of the inventlon also preferably contaln at least oneanlmal-derlved protelnaceous meal such as meat meal, bone meal and flsh meal. A good blscult dough for produclng the bls-cults of the lnventlon contalns about 50 to 60 percent by welght of wheat flour, about 5 to 10 percent by weight of soybean meal, about 3 to 10 percent by welght of meat and bone meal, about 1 to 5 percent of wheat meal, about 1 to 5 percent of animal fat preserved with BHA, about 20 to 30 percent by weight of water, and about

2 to 5 percent by weight of natural flavors, vitamin and mineral preblend, and acidulant.
The solvent used in preparing the dog biscuit dough, or for incorporating certain ingredients therein, is most preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used. The problem of the necessity of solvent removal from the dough due to toxicity is to be avoided in most cases. If a mixture of ethanol and water is used, the amount of ethanol in the mixture is generally about 5 to about 60 percent, preferably about 5 to about 25 percent. When one or more of the inorganic pyrophosphates is not water soluble, it may be ethanol soluble. It may be necessary to use a non-aqueous solvent, or mixture of water therewith, to incorporate the inorganic pyrophosphate.
The invention includes the use of at least one inorganic pyrophosphate. Preferably the inorganic pyrophosphates are water soluble or preferably a mixture of water soluble and water insoluble inorganic pyrophosphates are used. Such a mixture is usually used to provide a desired pH. The use of water-insoluble or difficultly soluble inorganic pyrophosphates in a dog biscuit dough is not a significant problem compared to use of such materials in a solution, such as, a mouth wash.
The pH of the dough can be adjusted using an inorganic base (e.g., KOH, NaOH, CaOH, LioH~ MgOH, etc.) or an inorganic 13~8179 acld (e.g., H2SO4, HCl, etc.), but this approach has the disadvantages of posslbly causlng a mlsbalance or overabundance of one or more chemlcal entities and possibly introduclng unwanted salts.
Generally 0.1 to 10 weight percent, advantageously about 0.5 to about 5 weight percent, of inorganic pyrophos-phate is used.
When a mixture of tetrasodium pyrophosphate (TSPP) and sodium acld pyrophosphate ln aqueous solutlon at the 5 weight percent level was incorporated in dog biscuit dough, there was reduced dough gluten development; the dog biscuits were bleached (whltish) and crumbly; and the dog biscuits were softer (a hardness problem) than the control dog biscuits. At the level of 3 weight percent of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate, the same problems occurred, but less severely. The addition of the lnorganlc pyrophosphates ln dry form to the dry lngredients in the dough preparation basically eliminated the above problems. It was also found that better results were secured by using the inorganlc phosphates ln powder form as opposed to granular form.
The inorganic pyrophosphates are preferably alkali metal pyrophosphates. The preferred alkall metal pyrophos-phates are tetrasodium pyrophosphate and tetropotassium pyro-phosphate. An example of a useful tetraalkall metal pyrophos-phate is tetralithium pyrophosphate. Alkaline earth metal pyrophosphates are also useful, but they are generally insoluble in water. Preferably, the inorganic pyrophosphates are soluble in water.
Kirk & Othmer, "Encyclopedia Of Chemical Technology", 2nd Ed., Vol. 15, (1965), pages 232 to 276, discloses a number of water-soluble inorganic pyrophosphate salts. The pertinent portions of Kirk & Othmer, "Encyclopedia Of Chemical Technology", 2nd Ed., Vol. 15, (1965), pages 232 to 276, are incorporated herein by reference.
Examples of dialkaline metal pyrophosphates are dicalcium pyrophosphate, dibarium pyrophosphate and dimagnesium pyrophosphate. Trialkali metal monoacid pyrophosphates,~such as, trisodium hydrogen pyrophosphate, can be used. Monoalkali metal triacid pyrophosphates, such as, sodium trihydrogen pyrophosphate, can also be present in limited amounts.
Examples of other inorganic pyrophosphates include manganese pyrophosphate and dizinc pyrophosphate.

The formula Mn+2PnO3n+1~ where M is a univalent metal, is the formula for univalent metal pyrophosphates when n is 2.
The formula M'nPnO3n+1, where M' is a divalent metal, is the formula for divalent metal pyrophosphates when n is 2. Such univalent metal pyrophosphates and divalent metal pyrophosphates can be used in the invention. Polyphosphates have the formula Mn+2PnO3n+, or M'nPnO3n+1, where n is 2, 3, 4, 5, ..., and the oxide ratio R between the cationic oxides (M20 or M'O) and anionic oxides (P205) is between 1 and 2. The oxide ratio for pyrophosphate is 2.
Tetrasodium pyrophosphate, one part, is soluble in 13 parts of cold water and in 2.5 parts of boiling water. It is insoluble in ethanol. Dicalcium pyrophosphate is practically insoluble in water. The invention use of the term "solution"
includes slurries, suspensions and the like. Tetrapotassium pyrophosphate is freely soluble in water and is insoluble in ethanol.
Advantageously a mixture of water-soluble tetrasodium pyrophosphate or tetrapotassium pyrophosphate and water-insoluble dicalcium pyrophosphate is used (in a ratio to achieve the desired pH). Most preferably a mixture of sodium acid pyrophosphate and tetrapotassium pyrophosphate is used (in a ratio to achieve the desired pH). In such most preferred mixture, tetrasodium pyrophosphate is not used as it would provide too much sodium in the composition.
The maximum allowable GRAS level in a composition for sodium acid pyrophosphate (SAPP) is 2.1 weight percent and tetrapotassium pyrophosphate (TKPP) is 1.4 weight percent in baked goods. If GRAS levels change (rise) or if higher levels are allowed by the regulatory agencies, higher levels can be used in the invention. TKPP delivers approximately 52.65 percent of P207; SAPP delivers about 78.36 percent of P207; and TSPP delivers about 65.4 percent of P207.
~ The most preferred invention dough contains trisodium monoacid pyrophosphate (that is, sodium acid pyrophosphate or SAPP) and tetrapotassium pyrophosphate in a weight ratio of about 60 to about 40.
The pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5, preferably from about 0.5 to about 3.5, most preferably 1.4 to 2.5 weight percent (based on the total composition), of P207.
A study of the application of aqueous solutions of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate to the teeth of dogs by spraying for one month resulted in dose response data. The aqueous solutions containing 5 and 3 weight percent of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate resulted in significant reductions in tartar accumulation. The aqueous solutions containing 1.5 and 0.5 weight percent of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate resulted in directional trends of reductions in tartar accumulation. See also U.S. Patent No. 3,323,551.
The ratio of sodium acid pyrophosphate (SAPP) to tetrapotassium pyrophosphate (TKPP) is generally between 4 to 1 and 3 to 7, preferably between 7 to 3 and 1 to 1, most preferably about 3 to about 2. SAPP has a pH of 4.2 and TKPP
(and TSPP) has a pH of 10.2, so the combination of SAPP and TKPP (or TSPP) provides a resultant pH which is a balance of the pHs of the two components.
The pH of the dough of at least one inorganic pyrophosphate compound (salt) is generally in the range of about 4 to about 10.5, typically from about 4.5 to about 7.5, preferably from about 5 to about 7, most preferably between about 5.6 and 6Ø Milk Bon ~ dog biscuit has a pH of 6.1 to 6.4. Tartar reduction is indicated to be best at neutral pH
and palatability is indicated to be best at a slightly acidic 133817~
pH, so the best mode contemplates a balance of such two factors.
The dough ingredient is generally mixed at a temperature of about 45 to about 140F, preferably about 60 to about 125F.
The dough can also contain suitable surfactants or emulsifying agents, e.g., cationic agents and nonionic agents.
Suitable nonionic emulsifying agents can be broadly defined as compounds produced by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound which can be aliphatic, alkyl aromatic, or a condensate of an alkylene oxide with an alkylene glycol in nature. Examples of suitable nonionic emulsifying agents include the Piuronics, polyethylene oxide condensates of alkyl phenols, products derived from the condensation of ethylene oxide with the reaction product of propylene oxide and ethylene diamine, ethylene oxide condensates of aliphatic alcohols, long chain tertiary amine oxides, long chain tertiary phosphine oxides, long chain dialkyl sulphoxides, and mixtures of such materials. The emulsifier is best used in minor amounts.
~ The dog biscuit dough can be mixed using any suitable or conventional equipment. For example, the mixing can be at 20 to 100 rpm. For example, a dry blending step (dries and the inorganic pyrophosphates) can be done typically at room temperature for a period of time of about 3 minutes to about 20 minutes. The dry-blended mixture can then be mixed with the hot water to form a first stage dough. The water which 133~179 can be admixed with the dry-blended mixture is typically at a temperature of about 65 to about 150F. The hot water can be added, with mixing, over a period of time of about 3 minutes to about 6 minutes to form the first stage dough. Then, the fat portion of the biscuit dough can be admixed with the first stage dough to form the final stage dough. The fat portion can be added at a temperature at which it is at least fluid, typically at about 100 to about 150F. The fat portion can be mixed for a period of time which is sufficient to form a dough whose homogeneity is visually apparent. A typically final mixing time is about 3 to about 5 minutes.
If there are machinability and dough structure property problems with the invention dough, the addition of water should solve such problems. If the use of the higher water levels causes the dough to be so sticky as to cause problems in a sigma or rotary mixer (but normally not a significant problem in a continuous mixer). The addition of more tallow to the dog biscuit dough should assist in more effective mixing and help to keep the dough from being so sticky that it clings to the rotary molder. Preferably the tallow level is about 2.6 to about 3.1 weight percent (most pr~ferably about 2.85 weight percent), as opposed to a tallow level of about 2Y46 weight percent in Milk Bone@~dog biscuits. Also, the tallow provides a taste which dogs like.
Formation of the dough is achieved at about atmospheric pressure with mixing of the components being conveniently achieved in an upright sigma blade mixer or other bakery-type mixers. The various ingredients can be added over a period of - 133817~

time or in a one-shot manner according to the above order of addition. However, melted fat and water can be added simultaneously and mixed for 6 to 10 minutes.
The dog biscuits are formed in any conventional or suitable manner, such as, by extrusion, stamping, cutting or molding. Any suitable dog biscuit shapes can be used, such as, a bone-shaped canine biscuit. For many products, such as, the bone-shaped canine biscuits of the invention, a rotary molding system is preferred because it permits the rapid forming of dough pieces with good control over their shape, form and surface characteristics. Docker holes are preferably formed in the dough piece during molding to facilitate the escape of moisture during baking.
The dough can then be formed into pieces by machining on a rotary molder with specific die shapes. The dough can also be formed into pieces by sheeting followed by either a vertical or rotary cutter or by a rotary molder. Suitable die and cutter shapes are those which result in a round, square, triangular, T-bone or chop-shaped biscuit product and the like. The forming is achieved at conventional temperatures of ambient to 110F and pressures of less than 75 p.s.i. (gauge), u~sed with a rotary molder, a vertical cutter or rotary cutter.
The dough pieces can be baked using any suitable or conventional equipment and conditions. For example, the dough pieces can be passed into an oven such as a conventional band oven where the biscuit is baked. The conveyer belts of the oven can be coated with an edible lubricant such as a natural or synthetic cooking oil or shortening to facilitate separation from the conveyer belts of the baked products.
Temperatures in the range of about 300 to about 600F can be used. The baked biscuits can also be subjected to subsequent drying at temperatures of about 200 to 400F, either within the baking oven or separately, to produce the desired moisture content in the final product.
The formed pieces are baked, followed by drying, to achieve a shelf stable product without the need of any moisture barrier protection. Baking and drying temperatures and times are those conventionally used in the production of a hard, dry canine biscuit. The pieces are dried to obtain a biscuit having a water activity of 0.70 or less. Typically, baking temperatures and times are about 300F to about an average of 475F for about 25 minutes to about 8 minutes.
Drying conditions are typically about 200 to about 325F for about 25 minutes to about 12 minutes in a forced air dryer.
On a weight basis, the moisture content of the final biscuit product is less than or equal to about 15 percent by weight and preferably about 10 to 12 percent by weight of the final biscuit at 70 percent relative humidity.
The ingredients, pH and ranges for the invention dough are the same for the invention dog biscuits.
The invention product is generally as palatable as Milk Bon ~ dog biscuits, which have been widely accepted and a commercial success for many years.
The invention product does not include any fluorine-containing compound or other fluoride ion source, or ~33817!~

quaternary ammonium compounds. Also the invention product does not include any organic pyrophosphates.
The invention deals primarily with dogs, but has a scope of teeth-bearing non-human mammals, such as, cats.
The invention composition is used to reduce and control tartar accumulation on canine teeth. Based upon the weight of commercial Milk Bon ~ dog biscuits: 12 small invention dog biscuits per day, 10 medium invention dog biscuits per day, 6 large invention dog biscuits per day or 4 extra large invention dog biscuits per day will supply about 1/4 to 1/3 of a dog's caloric requirement.
The invention also involves a process for preparing dog biscuit dough which is nutritionally balanced and which contains at least one inorganic pyrophosphate. The process includes admixing the ingredients of the dog biscuit dough and the at least one inorganic pyrophosphate. The ingredients and the at least one inorganic pyrophosphate are selected and adjusted in amounts which provide a nutritional balance. The inorganic pyrophosphate also reduces the accumulation of tartar on the teeth of dogs.
Preferably the dry dough ingredients and the inorganic pyrophosphate salts are mixed, then water is added and the mixing continued, and finally the fat (tallow) is added and thoroughly mixed in.
The dog biscuits can be made from any suitable dough. In one advantageous embodiment, a bone-shaped canine biscuit is provided which is baked from a dough comprising wheat flour, wheat meal, soybean meal, meat and bone meals, animal fat and 1~38179 water. The baked dog blscult has an overall molsture content of 13 weight percent or less.
The composltlons of the dog blscult doughs are mod-lfied as descrlbed hereln to provlde nutrltlonally-balanced dog blscults.
The lnventlon also lnvolves dog blscult dough whlch is nutrltlonally balanced and whlch contalns at least one lnorganlc pyrophosphate. Generally, the lnventlon dog blscult dough contalns: about 0.1 to about 7 welght percent of Ca, about 0.08 to about 6 welght percent of P, about 0.05 to about

3 weight percent of K, about 0.1 to about 3 weight percent of Na and about 0.15 to about 4.5 welght percent of Cl , prefer-ably about 0.5 to about 4 welght percent of Ca, about 0.4 to about 3 welght percent of P, about 0.15 to about 3 welght percent of K, about 0.2 to about 2.0 welght percent of Na and about 0.3 to about 3 welght percent of Cl ; and most prefer-ably about 1.0 to about 2.5 welght percent of Ca, about 0.8 to about 2.0 welght percent of P, about 0.25 to about 2.0 welght percent of K, about 0.3 to about 1.0 welght percent of Na and about 0.45 to about 1.5 welght percent of Cl . The above welght percentages are based upon the entlre welght of the dog blscult doughs (or unbaked dog blscults or baked dog bls-cults), assumlng a water content of 10 welght percent for these calculatlons. Preferably the ratlo of Ca to P ls between about 1.0:1 and about 1.6:1, and most preferably the ratio of Ca to P is between about 1.1:1 and about 1.4:1.
One of the keys to the lnvention ls the selectlon and ad~ustment ln amounts of the dog blscult dough ingredients and ~ 73783-60 13381~9 the at least one inorganic pyrophosphate salt to provide a nutritional balance.
The dog biscuit dough preferably contains about 0.1 to about 10 weight percent of the at least one inorganic pyrophosphate compound, and most preferably about 0.5 to about 5 weight percent of said at least one inorganic pyrophosphate compound. The preferred inorganic pyrophosphate salt(s) is an alkali metal pyrophosphate. Most preferably the dog biscuit dough contains a combination of sodium acid pyrophosphate and tetrapotassium pyrophosphate.
The invention also involves a process for preparing unbaked dog biscuits from the dog biscuit dough. The invention also involves unbaked dog biscuits which are nutritionally balanced and which contain at least one inorganic pyrophosphate. The dog biscuit pieces preferably are bone shaped. The unbaked dog biscuits have a moisture content usually in the range of about 25 to about 40 weight percent, preferably about 33 to about 35 weight percent.
The invention also involves a process for preparing baked dog biscuits which are nutritionally balanced and which contain at least one inorganic pyrophosphate. The process ~ncludes:
(a) shaping a dog biscuit dough, which is nutritionally balanced and which contains the at least one inorganic pyrophosphate, into dog biscuit pieces comprising unbaked dog biscuits; and (b) baking the unbaked dog biscuits.

133~17~

The baked dog biscuits can be dried, if necessary, to obtain the desired moisture level. The baked dog biscuits should have a moisture content of 13 weight percent or less, advantageously between about 5 and 13 weight percent, and preferably between about 8 and about 12 weight percent. The invention product is baked so that it comprises a baked dog biscuit which is nutritionally balanced and which contains at least one inorganic pyrophosphate.
The invention further involves baked dog biscuits which are nutritionally balanced and which contain at least one inorganic pyrophosphate. The ingredients, ratios, ranges, etc., for the invention dog biscuit dough applies to the invention baked dog biscuits except as otherwise noted herein.
The invention product preferably should be slightly acid to neutral.
The inorganic pyrophosphates are anti-tartar, anti-plaque or anti-calculus agents. The invention product exhibits anti-tartar properties over its normal shelf life. The invention product does not adversely affect canine tooth enamel.
The invention further involves a process for the prevention or reduction of tartar accumulation on the teeth of dogs. The process includes the chewing and/or eating of the invention baked dog biscuits by the dogs. The term "dog biscuit" herein means a baked dog biscuit unless otherwise stated herein or otherwise obvious herefrom to one skilled in the art.
The invention biscuits, when eaten and chewed by dogs, cleans teeth surfaces, removes tartar (by mechanical action), and exercises and massages the gums. The pyrophosphate ln the lnventlon blscuits prevents or reduces the formation of tartar on the dog's teeth. The pyrophosphate, in the levels involved, does not adversely affect the gastrolntestlnal system or the health of the dogs.
The dog biscuits can be made from any suitable dough, which is modified as described herein to provide nutrition-ally-balanced dog blscuits contalning pyrophosphate.
Any suitable dough comprising at least one flour, meal, fat and water can be employed for the product. For instance, when the desired product is a canine biscuit, a conventional dough for dog biscuits can be used, optionally containing discrete particles of meat and/or meat byproducts or farinaceous material. Such doughs typically contain fat solids. Examples of suitable doughs for the production of hard dog biscuits are disclosed in U.S. Patent No. 4,454,163, and suitable doughs for the production of soft dog blscuits ~containing humectant to control water activity) are disclosed in U.S. Patent No. 4,454,164. Particulate proteinaceous particles, such as, particles of meat, texturized vegetable proteln and/or meat byproducts, can be incorporated to add flavor to the blscuits and texturize the surface. Particulate farinaceous materials, such as, bran particles, can also be employed to texturlze the interior and/or surface of the blscuits and to provide other useful properties to the prod-uct. A dough found to produce blscuits hlghly palatable to dogs lncludes sultable proportlons of wheat flour, wheat meal, soybean meal, meat and bone meal, anlmal fat and natural flavors ln admlxture wlth water. The meal used in the doughs suitable for production of biscults useful in the invention can comprise meat and/or bone andtor vegetable matter includ-lng farlnaceous materials, materials prepared from legumes such as beans and peas, tuberous materlals such as potato meal, and the like. The meals can be finely or coarsely ground as desired for the texture. Flours made from any sultable farlnaceous materlal can be used.
The doughs generally have a water actlvlty of about 0.90 and above upon completion of mixing of the dough ingredi-ents. A suitable dough contains farinaceous material, an edible oil, an antioxidant, an antimycotlc, salt, anlmal fat, added vltamlns and mlnerals, such as those disclosed in U.S.
Patent No. 4,229,485, column 5, lines 7 to 57. The composi-tions of the lnventlon also preferably contain at least one animal-derived protelnaceous meal such as meat meal, bone meal and flsh meal. A good biscuit dough for producing the bis-cults of the invention contains about 50 to 60 percent by weight of wheat flour, about 5 to 10 percent by weight of soybean meal, about 3 to 10 percent by weight of meat and bone meal, about 1 to 5 percent of wheat meal, about 1 to 5 percent of animal fat preserved with BHA, about 20 to 30 percent by welght of water, and about 2 to 5 percent by weight of natural flavors, vitamln and mlneral preblend, and acidulant.

-The dog biscuit doughs are modified as described herein to provide nutritionally-balanced dog biscuits.
The solvent used in preparing the dog biscuit dough is preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used. The problem of the necessity of solvent removal from the dough due to toxicity is to be avoided in most cases. If a mixture of ethanol and water is used, the amount of ethanol in the mixture is generally about 5 to about 60 percent, preferably about 5 to about 25 percent. When one or more of the inorganic pyrophosphates is not water soluble, it may be ethanol soluble.
The invention includes the use of at least one inorganic pyrophosphate. Preferably the inorganic pyrophosphates are water soluble. A mixture of inorganic pyrophosphates can be used to help secure a nutritional balance and can be used to provide a desired pH. The use of water-insoluble or difficultly soluble inorganic pyrophosphates in a dog biscuit dough is not a significant problem compared to use of such materials in a solution, such as, a mouth wash.
The pH of the dough can be adjusted using an inorganic base (e.g., KOH, NaOH, CaOH, LioH, MgOH, etc.) or an inorganic acid (e.g., H2SO4, HCl, etc.), but this approach has the disadvantages of possibly causing a misbalance or overabundance of one or more chemical entities and possibly introducing unwanted salts.

Generally 0.1 to 10 weight percent, preferably about 0.5 to about 3.5 weight percent and preferably about 1.4 to about 2.5 weight percent of inorganic pyrophosphate is used.
When a mixture of tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate in aqueous solution at the 5 weight percent level was incorporated in dog biscuit dough, there was reduced dough gluten development, the dog biscuits were bleached (whitish) and crumbly, and the dog biscuits were softer (a hardness problem) than the control dog biscuits.
Also, such dog biscuits had nutrition problems. At the level of 3 weight percent of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate, the same problems occurred, but less severely. The addition of the inorganic pyrophosphates in dry form to the dry ingredients in the dough preparation basically eliminated the above problems (except for the nutrition problem). It was also found that better results were secured by using the inorganic phosphates in powder form as opposed to granular form.
The inorganic pyrophosphates are preferably alkali metal pyrophosphates. The preferred alkali metal pyrophosphates are tetrasodium pyrophosphate and tetrapotassium pyrophosphate.
An example of useful a tetraalkali metal pyrophosphate is tetralithium pyrophosphate. Alkaline earth metal pyrophosphates are also useful, but they are generally insoluble in water. Preferably the inorganic pyrophosphates are soluble in water.
Kirk & Othmer, "Encyclopedia Of Chemical Technology", 2nd Ed., Vol. 15, (1965), pages 232 to 276, discloses a number of 133817g water-soluble lnorganlc pyrophosphate salts.
Examples of dlalkallne metal pyrophosphates are dlcalclum pyrophosphate, dlbarlum pyrophosphate and dlmag-neslum pyrophosphate. Trlalkall metal monoacld pyrophos-phates, such as, trlsodlum hydrogen pyrophosphate (SAPP), can be used. Monoalkall metal trlacld pyrophosphates, such as, sodlum trlhydrogen pyrophosphate, can also be present ln llmlted amounts. Examples of other lnorganlc pyrophosphates lnclude manganese pyrophosphate and dlzlnc pyrophosphate.
n+2PnO3n+l, where M ls a unlvalent metal, ls the formula for unlvalent metal pyrophosphates when n ls 2. The formula M'nPnO3n+l, where M' ls a dlvalent metal, ls the formula for dlvalent metal pyrophosphates when n ls 2.
Such unlvalent metal pyrophosphates and dlvalent metal pyro-phosphates can be used ln the lnventlon. Polyphosphates have the formula Mn+2PnO3n+l or M nPn3n+1 5,..., and the oxlde ratlo R between the catlonlc oxldes (M2O
or M'O) and anlonlc oxldes (P2O5) ls between 1 and 2. The oxlde ratlo for pyrophosphate ls 2.
Tetrasodlum pyrophosphate, one part, ls soluble ln 13 parts of cold water and ln 2.5 parts of bolllng water. It ls lnsoluble ln ethanol. Dlcalclum pyrophosphate ls practlcally lnsoluble ln water. The lnventlon use of the term "solutlon"
lncludes slurrles, suspenslons and the llke. Tetrapotasslum 133817~

pyrophosphate is freely soluble in water and is insoluble in ethanol.
Most preferably a mixture of sodium acid pyrophosphate and tetrapotassium pyrophosphate is used (in a ratio to achieve the desired nutritional delivery and the desired pH).
In such most preferred mixture, tetrasodium pyrophosphate is not used as it would provide too much sodium in the nutritionally-balanced composition.
The maximum allowable GRAS level in the U.S. in a composition for sodium acid pyrophosphate (SAPP) is 2.1 weight percent and tetrapotassium pyrophosphate (TKPP) is 1.4 weight percent in baked goods. If GRAS levels change (rise) or if higher levels are allowed by the regulatory agencies, higher levels can be used in the invention. TKPP delivers approximately 52.65 percent of P2O7; SAPP delivers about 78.36 percent of P207; and TSPP delivers about 65.4 percent of P207.
With the total amount of Na and Cl in the dog biscuit dough (or baked dog biscuit) being taken as 100 weight percent, preferably the Na content ranges between about 30 and about 50 weight percent and the Cl- content ranges between about 50 and about 70 weight percent, and most preferably the ~a content is about 40 to about 44 weight percent and the Cl--content is about 60 to about 56 weight percent.
The pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5, preferably from about 0.5 to about 3.5 weight percent, most preferably 1.4 to 2.5 weight percent (based on the total composition), of P207.

13381~ ~
The use of 3.5 welght percent of lnorganic pyrophosphate salt(s) means the delivery of about 2.5 welght percent of P207 ~
A study of the appllcatlon of aqueous solutlons of a mlxture of tetrasodlum pyrophosphate and sodium acld pyrophos-phate to the teeth of dogs by spraylng for one month resulted ln dose response data. The aqueous solutlons contalnlng 5 and 3 welght percent of a mixture of tetrasodlum pyrophosphate and sodlum acld pyrophosphate resulted ln slgnlflcant reductlons ln tartar accumulatlon. The aqueous solutlons contalnlng 1.5 and 0.5 weight percent of a mlxture of sodlum acld pyrophos-phate and tetrasodlum pyrophosphate resulted ln dlrectlonal trends of reductlons ln tartar accumulatlon. See also U.S.
Patent No. 3,323,551.
The ratlo of sodlum acld pyrophosphate (SAPP) to tetrapotasslum pyrophosphate (TKPP) ls generally between 4 to 1 and 3 to 7, preferably between 7 to 3 and 1 to 1, most preferably about 3 to about 2. SAPP has a pH of 4.2 and TKPP
(and TSPP) has a pH of 10.2, so the combinatlon of SAPP and TKPP (or TSPP) provldes a resultant pH whlch ls a balance of the pHs of the two components.
The pH of the dough contalnlng at least one lnorganlc pyrophosphate salt (and baked dog blscult) ls generally ln the range of about 4 to about 10.5, typlcally from about 4.5 to about 7.5, preferably from about 5 to about 7, most preferably between about 5.6 and about 6.1. Mllk ~30ne~ dog blscult has a pH of 6.1 to 6.4. Tartar reductlon ls lndlcated to be best at neutral pH and palatablllty ls lndicated to be best at a 13381~ 9 slightly acidic pH, so the best mode contemplates a balance of such two factors ln any commerclal product.
The dough ingredlent ls generally mlxed at a tempera-ture of about 45 to about 140F, preferably about 60 to about 125F.
The nutritlonally-balanced dog blscult dough gen-erally contalns about 0.1 to about 7 welght percent of Ca, about 0.08 to about 6 welght percent of P, about 0.05 to about 3 welght percent of K, about 0.1 to about 3 welght percent of Na and about 0.15 to about 4.5 welght percent of Cl . The nutritionally-balanced dog blscuit dough preferably contalns about 0.5 to about 4 welght percent of Ca, about 0.4 to about 3 welght percent of P, about 0.15 to about 3 welght percent of K, about 0.2 to about 2 welght percent of Na and about 0.3 to about 3 welght percent of Cl , and most preferably contalns about 1.0 to about 2.5 welght percent-of Ca, about 0.8 to about 2.0 welght percent of P, about 0.25 to about 2.0 welght percent of K, about 0.3 to about 1.0 weight percent of Na and about 0.45 to about 1.5 welght percent of Cl . The above welght percentages are based upon the entire weight of the dog biscuit doughs (or unbaked dog blscults or baked dog bls-cults), assumlng a water content of 10 percent for these calculations. Mlnor nutrltlonal elements can also be ad~usted as deslred.
The lnventlon is ln llne wlth the nutrltlonal requlrements of dogs for malntenance as regards calcium, phosphorus, potasslum, sodlum and chlorlne. Examples lO and 11 are also nutrltlonally complete wlth regard to 1~38179 micronutrients. Puppies need high Ca and P for growth. Milk Bone~ dog biscuits are nutritionally balanced.
The ratio of Ca to P in the nutritionally-balanced dog biscuit dough is generally, preferably between about 1.0:1 and about 1.6:1, and most preferably between about 1.2:1 and about 1.4:1.
The critical factor in the prevention or reduction of tartar accumulation is the pyrophosphate moiety. The nutritional balance partially depends upon the amounts and ratios of elements and ions, such as Ca, P, K, Na and Cl-.
The reason that it is best to use tetrapotassium pyrophosphate, instead of tetrasodium pyrophosphate, with sodium acid pyrophosphate is that such action holds down the sodium level in the dough.
In order to provide sufficient calcium to achieve nutritional balance, calcium carbonate and calcium chloride are included in the preferred invention formula. It is advantageous to use calcium chloride (to raise the chlorine level) and a high level of calcium carbonate instead of the dicalcium phosphate and the low level of calcium carbonate used in Milk Bone~ dog biscuits. Also, since the invention uses pyrophosphates, the P level could be too high if dicalcium phosphate is also used. The calcium chloride supplies Cl- to help achieve nutritional balance. The calcium chloride can be replaced by dicalcium pyrophosphate (with a corresponding adjustment of the other pyrophosphate salts and possible addition of another chlorine source). The bone meal level in Milk Bon ~ dog biscuits has been lowered in the preferred invention formula.
The invention biscuits do not include the salt present in Milk Bon ~ dog biscuits.
The dough can also contain suitable surfactants or emulsifying agents, best used in minor amounts.
The dog biscuit dough can be mixed using any suitable or conventional equipment. For example, the mixing can be at 20 to 100 rpm. For example, a dry blending step (dries and the inorganic pyrophosphates) can be done typically at room temperature for a period of time of about 3 minutes to about 20 minutes. The dry-blended mixture can then be mixed with the hot water to form a first stage dough. The water which can be admixed with the dry-blended mixture is typically at a temperature of about 65 to about 150F. The hot water can be added, with mixing, over a period of time of about 3 minutes to about 6 minutes to form the first stage dough. Then, the fat portion of the biscuit dough can be admixed with the first stage dough to form the final stage dough. The fat portion can be added at a temperature at which it is at least fluid, typically at about 100 to about 150F. The fat portion can be ~ixed for a period of time which is sufficient to form a dough whose homogeneity is visually apparent. A typically final mixing time is about 3 to about 5 minutes.
Initially, there were machinability and dough structure property problems with the invention dough, but the addition of water solved such problems. But the use of the higher water levels caused the dough to be so sticky as to cause 1~3817~

problems in a sigma or rotary mixer (but it is normally not a slgnlflcant problem ln a continuous mlxer). The addltlon of more tallow to the dog blscult dough assisted ln more effec-tlve mlxlng and helped to keep the dough from belng so stlcky that lt cllngs to the rotary molder. Preferably the tallow level ls about 2.6 to about 3.1 welght percent ~most preferab-ly about 2.85 welght percent), as opposed to a tallow level of about 2.46 welght percent ln Mllk Bone~ dog blscults. Also, the tallow provldes a taste whlch dogs llke.
Formatlon of the dough ls achleved at about atmos-pherlc pressure wlth mlxing of the components being conveni-ently achleved in an uprlght slgma blade mixer or other bakery-type mixers. The various ingredlents can be added over a period of tlme or ln a one-shot manner accordlng to the above order of addltion. However, melted fat and water can be added slmultaneously and mlxed for 6 to 10 mlnutes.
The dog blscults are formed ln any conventlonal or sultable manner, such as, by extruslon, stamplng, cuttlng or moldlng. Any sultable dog blscult shapes can be used, such as, a bone-shaped canlne blscult. For many products, such as, the bone-shaped canlne blscults of the lnventlon, a rotary molding system ls preferred because lt permlts the rapld formlng of dough pleces wlth good control over thelr shape, form and surface characterlstlcs. Docker holes are preferably formed ln the dough plece durlng moldlng to facllltate the escape of molsture durlng baklng.
The dough can then be formed lnto pleces by machlnlng on a rotary molder wlth speclflc dle shapes. The dough can also be formed lnto pieces by sheetlng followed by either a vertlcal or rotary cutter or by a rotary molder. Suitable die and cutter shapes are those which result in a round, square, trlangular, T-bone or chop-shaped biscult product and the llke. The formlng ls achleved at conventlonal temperatures of amblent to 110F and pressures of less than 75 p.s.l. (gauge), used wlth a rotary molder, a vertical cutter or rotary cutter.
The dough pleces can be baked uslng any sultable or conventional equlpment and conditlons. For example, the dough pleces can be passed lnto an oven such as a conventlonal band oven where the blscuit ls baked. The conveyer belts of the oven can be coated wlth an edlble lubricant such as a natural or synthetlc cooking oil or shortenlng to facilitate separ-ation from the conveyer belts of the baked products. Tempera-tures ln the range of about 300 to about 600F can be used.
The baked biscults can also be sub~ected to subsequent drying at temperatures of about 200 to 400F, either wlthln the baklng oven or separately, to produce the deslred molsture content ln the flnal product.
The formed pleces are baked, followed by drylng, to achieve a shelf stable product wlthout the need of any mols-ture barrler protectlon. Baklng and drylng temperatures and tlmes are those conventlonally used in the productlon of a hard, dry canlne blscult. The pleces are drled to obtaln a blscult havlng a water actlvlty of 0.70 or less. Typlcally, baklng temperatures and tlmes are about 300F to about an average of 475F for about 25 mlnutes to about 8 mlnutes.
Drylng condltions are typlcally about 200 to about 325F for 13~8179 about 25 minutes to about 12 minutes in a forced air dryer.
On a weight basis, the moisture content of the final biscuit product is less than or equal to 13 percent by weight, usually at least 5 weight percent, and most preferably about 8 to about 12 percent by weight, of the final biscuit at 70 percent relative humidity.
The ingredients, pH and ranges for the invention dough are the same for the invention dog biscuits.
The invention product is similar as palatable as Milk Bon ~ dog biscuits, which have been widely accepted and a commercial success for many years.
The invention product does not include any fluorine-containing compound or other fluoride ion source, or quaternary ammonium compounds. Also the invention product does not include any organic pyrophosphates.
The invention deals primarily with dogs, but has a scope of teeth-bearing non-human mammals, such as, cats.
The invention composition is used to reduce and control tartar accumulation on canine teeth. Based upon the weight of commercial Milk Bon ~ dog biscuits: 12 small invention dog biscuits per day, 10 medium invention dog biscuits per day, 6 large invention dog biscuits per day or 4 extra large invention dog biscuits per day will supply about 1/4 to 1/3 of a dog's caloric requirement.
The following table sets out the content of nutritionally important elements and ions in various dog biscuits:

Table 1 1.6% 2.34%
Pyrophosphate Pyrophosphate Milk Bon ~ Example lla Example 10 Elements Dog Biscuits Dog Biscuits Dog Biscuits Or Ions Wt. Percent Wt. Percent Wt. Percent Ca 1.21 1.581 1.843 P 0.978 1.333 1.585 K 0.846 1.105 1.252 Na 0.413 0.488 0.516 Cl-- 0.524 0.651 0.662 OTES: 1. Milk Bone~ is a registered trademark of Nabisco Brands, Inc. for canine biscuits.
2. The ratio of Ca to P is 1.1-1.2 to 1 in Milk Bon ~ canine biscuits.
3. The weight percentages are based on the final canine biscuits having a moisture content of 10 percent.

4. The Examples 10, lla and llb formulas are the most preferred compositions.
It is most preferred to have a chlorine content of about 40 to about 44 weight percent and a Na content of about 60 to about 56 weight percent, based on the total weight of Na and Cl in the dog biscuit. The most preferred calcium/phosphorus ratio of 1.1-1.4:1 is best for growth and maintenance.
The invention also includes a process for preparing dog biscuit dough having a coating containing at ~east one inorganic pyrophosphate compound, which includes preparing a dog biscuit dough, forming the dog biscuit dough into pieces, subjecting the dog biscuit dough pieces to a liquefied coating material having at least one inorganic pyrophosphate, thereby forming a coating of such liquefied coating material on the dog biscuit dough pieces, and baking (and optionally drying) the dog biscuit dough pieces having a coating containing at least one inorganic 13381~9 pyrophosphate. The lnorganlc pyrophosphate reduces the accu-mulatlon of tartar on the teeth of dogs.
Preferably the dry dough ingredlents are mixed, then water ls added and the mlxlng contlnued, and finally the fat (tallow) ls added and thoroughly mlxed ln. The dog blscults can be made from any sultable dough. In one advantageous embodiment, a bone-shaped canlne blscult ls provlded whlch ls baked from a dough comprlslng wheat flour, wheat meal, soybean meal, meat and bone meals, animal fat and water. The baked, coated biscult has an overall molsture content of 13 welght percent or less.
The coatlng on the dog blscult dough preferably contalns about 0.1 to about 10 welght percent of the at least one lnorganlc pyrophosphate compound, and most preferably about 0.5 to about 5 welght percent of sald at least one inorganic pyrophosphate compound. The preferred lnorganic pyrophosphate salt(s) ls an alkall metal pyrophosphate. Whlle the preferred alkall metal pyrophosphate ls tetrasodlum pyrophosphate, most preferably the dog blscult dough contalns a comblnatlon of trlsodlum monoacld pyrophosphate and tetrapotasslum pyrophosphate (or tetrasodlum pyrophosphate).
The lnvention also involves unbaked dog blscuits whlch have a coatlng whlch contalns at least one lnorganlc pyrophosphate. The dog blscult pleces preferably are bone shaped. The unbaked dog blscuits preferably have a moisture content usually ln the range of about 25 to about 40 welght percent, preferably about 33 to about 35 welght percent.

73783-~0 The invention also involves a process for preparing baked dog biscuits which have a baked coating containing at least one inorganic pyrophosphate. The process includes:
(a) placing a coating, balanced and which contains the at least one inorganic pyrophosphate, onto unbaked dog biscuit dough pieces comprising unbaked dog biscuits; and (b) baking the coated, unbaked dog biscuits.
The baked dog biscuits can be dried, if necessary, to obtain the desired moisture level. The baked dog biscuits should have a moisture content of 13 weight percent or less, advantageously between 5 and 13 weight percent, and preferably between about 8 and about 12 weight percent.
The invention product is baked so that it comprises a baked dog biscuit which has a coating containing at least one inorganic pyrophosphate.
The invention further involves baked, coated dog biscuits, such coating containing at least one inorganic pyrophosphate.
The ingredients, ratios, ranges, etc., for the invention dog biscuit dough and coating applies to the invention baked, coated dog biscuits, except as otherwise noted herein.
The invention product (including coating) should be s~lightly acid to neutral.
The inorganic pyrophosphates are anti-tartar, anti-plaque or anti-calculus agents. The invention product exhibits anti-tartar properties over its normal shelf life. The invention product does not adversely affect canine tooth enamel.
The invention further involves a process for the prevention or reduction of tartar accumulation on the teeth of dogs. The 133817~
process includes the chewing and/or eatlng of the lnventlon baked, coated dog blscults by the dogs.
The lnventlon blscults, when eaten and chewed by dogs, cleans teeth surfaces, removes tartar (by mechanlcal actlon), and exerclses and massages the gums. The pyrophos-phate ln the coatlng of the lnventlon blscults prevents or reduces the formatlon of tartar on the dog's teeth. The pyrophosphate, ln the levels lnvolved, does not adversely affect the gastrolntestlnal system or the health of the dogs.
The dog blscults can be made from any sultable dough, whlch ls modlfied as descrlbed hereln to provlde nutrltlon-ally-balanced dog blscults contalnlng pyrophosphate.
Any sultable dough comprlslng at least one flour, meal, fat and water can be employed for the coated product.
For lnstance, when the deslred product ls a canlne blscuit, a conventlonal dough for dog blscults can be used, optlonally contalnlng dlscrete partlcles of meat and/or meat byproducts or farlnaceous materlal. Such doughs typlcally contaln fat sollds. Examples of sultable doughs for the productlon of Z0 hard dog blscuits are dlsclosed ln U.S. Patent No. 4,454,163, and sultable doughs for the productlon of soft dog blscults (contalnlng humectant to control water actlvlty) are dlsclosed ln U.S. Patent No. 4,454,164. Partlculate protelnaceous partlcles, such as, partlcles of meat, texturlzed vegetable proteln and/or meat byproducts, can be lncorporated to add flavor to the blscults and texturlze the surface. Partlculate farlnaceous materlals, such as, bran partlcles, can also be employed to texturlze the surface of the blscults and to provlde other useful propertles to the product. A dough found 133817~
to produce blscuits highly palatable to dogs lncludes sultable proportlons of wheat flour, wheat meal, soybean meal, meat and bone meal, animal fat and natural flavors in admixture with water. The meal used ln the doughs sultable for productlon of biscults useful in the lnvention can comprise meat and/or bone and/or vegetable matter lncluding farlnaceous materlals, materlals prepared from legumes such as beans and peas, tuber-ous materlals such as potato meal, and the llke. The meals can be finely or coarsely ground as desired for the texture.
Flours made from any suitable farlnaceous materlal can be used.
The doughs generally have a water actlvlty of about 0.90 and above upon completlon of mixlng of the dough ingredi-ents. A suitable dough contains farinaceous material, an edible oil, an antioxidant, an antimycotlc, salt, animal fat, added vltamlns and mlnerals, such as those dlsclosed in U.S.
Patent No. 4,229,485, column 5, llnes 7 to 57. The composl-tions of the lnventlon also preferably contain at least one animal-derlved proteinaceous meal such as meat meal, bone meal and fish meal. A good biscuit dough for producing the bis-cuits of the invention contains about 50 to 60 percent by weight of wheat flour, about 5 to 10 percent by weight of soybean meal, about 3 to 10 percent by weight of meat and bone meal, about 1 to 5 percent of wheat meal, about 1 to 5 percent of animal fat preserved with BHA, about 20 to 30 percent by weight of water, and about 2 percent by weight of natural flavors, vitamin and mlneral preblend, and acldulant.
The dough can also contaln sultable surfactants or emulslfying agents, e.g., whlch are best used ln mlnor amounts. 133817 9 The dog biscult dough can be mlxed uslng any sultable or conventlonal equlpment. For example, the mlxlng can be at 20 to 100 rpm. For example, a dry blending step can be done typically at room temperature for a perlod of tlme of about 3 mlnutes to about 10 mlnutes. The dry-blended mlxture can then be mlxed wlth the hot water to form a flrst stage dough. The water whlch can be admixed wlth the dry-blended mlxture is typlcally at a temperature of about 65 to about 150F. The hot water can be added, with mixing, over a perlod of tlme of about 3 mlnutes to about 5 mlnutes to form the flrst stage dough. Then, the fat portlon of the blscult dough can be admlxed wlth the flrst stage dough to form the flnal stage dough. The fat portlon can be added at a temperature at which it is at least fluid, typically at about 100 to about 150F.
The fat portion can be mixed for a period of time whlch ls sufficient to form a dough whose homogeneity ls vlsually apparent. A typically flnal mixlng tlme ls about 3 to about 5 minutes.
Formatlon of the dough ls usually achleved at about atmospherlc pressure wlth mlxlng of the components belng convenlently achleved ln an uprlght slgma blade mlxer or other bakery-type mlxers. The varlous lngredlents can be added over a perlod of tlme or ln a one-shot manner accordlng to the above order of addltlon. However, melted fat and water can be added slmultaneously and mlxed from 6 to lO mlnutes.
The dog blscults are formed ln any conventlonal or sultable manner, such as, by extruslon, stamplng, cuttlng or moldlng.

133~179 Any suitable dog biscuit shapes can be used, such as, a bone-shaped canine biscuit. For many products, such as, the bone-shaped canine biscuits of the invention, a rotary molding system is preferred because it permits the rapid forming of dough pieces with good control over their shape, form and surface characteristics. Docker holes are preferably formed in the dough piece during molding to facilitate the escape of moisture during baking.
The dough can be then formed into pieces by machining on a rotary molder with specific die shapes. The dough can also be formed into pieces by sheeting followed by either a vertical or rotary cutter or by a rotary molder. Suitable die and cutter shapes are those which result in a round, square, triangular, T-bone or chop-shaped biscuit product and the like. The forming is achieved at conventional temperatures of ambient to 110F and pressures of less than 75 p.s.i. (gauge), used with a rotary molder, a vertical cutter or rotary cutter.
The solvent used in the coating is preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used. The problem of the necessity of solvent removal from the coated dough due to toxicity is to be ~voided in most cases. If a mixture of ethanol and water is used, the amount of ethanol in the mixture is generally about 5 to about 60 percent, preferably about 5 to about 25 percent.
when one or more of the inorganic pyrophosphates is not water soluble, it may be ethanol soluble.
The invention includes the use of at least one inorganic pyrophosphate. Preferably the inorganic pyrophosphates are water soluble. A mixture of inorganic pyrophosphates can be used to provide a desired pH. The use of a water insoluble inorganic pyrophosphate, by itself or in a mixture, (along with the other water insoluble ingredients) results in a slurry. The use of very fine particles of a water insoluble inorganic pyrophosphate provides better suspension in the coating formulation.
The inorganic pyrophosphates are preferably alkali metal pyrophosphates. The preferred alkali metal pyrophosphate is tetrasodium pyrophosphate and tetrapotassium pyrophosphate. An example of useful tetraalkali metal pyrophosphates is tetralithium pyrophosphates. Alkaline earth metal pyrophosphates are also useful, but they are generally insoluble in water.
Preferably the inorganic pyrophosphates are soluble in water.
The formula Mn+2PnO3n+, where M is a univalent metal, is the formula for univalent metal pyrophosphates when n is 2. The formula M'nPnO3n+~ or where M' is a divalent metal, is the formula for divalent metal pyrophosphates when n is 2. Such univalent metal pyrophosphates and divalent metal pyrophosphates can be used in the invention. Polyphosphates have the formula Mn+2PnO3n+~
or M'nPnO3n+~. where n is 2, 3, 4, 5, ..., and the oxide ratio R
~etween the cationic oxides (M20 or M'O) and anionic oxides (P205) is between 1 and 2. The oxide ratio for pyrophosphate is 2.
Generally 0.1 to 10 weight percent, advantageously about 0.5 to about 5 weight percent and preferably about 1.5 to about 3 weight percent of inorganic pyrophosphate is used.
Kirk & Othmer, "Encyclopedia Of Chemical Technology", 2nd Ed., Vol. 15, (1965), pages 232 to 276, discloses a number of water-soluble lnorganlc pyrophosphate salts.
Examples of dlalkallne metal pyrophosphates are dlcalclum pyrophosphate, dlbarlum pyrophosphate and dlmag-neslum pyrophosphate. Trlalkall metal monoacld pyrophos-phates, such as, trlsodlum hydrogen pyrophosphate (SAPP), can be used. Monoalkall metal trlacld pyrophosphates, such as, sodium trlhydrogen pyrophosphate, can also be present ln llmlted amounts. Examples of other lnorganlc pyrophosphates include dlmanganese pyrophosphate and dlzlnc pyrophosphate.
Tetrasodlum pyrophosphate, one part, ls soluble ln 13 parts of cold water and ln 2.5 parts of bolllng water. It ls lnsoluble ln ethanol. Dlcalclum pyrophosphate ls practlcally lnsoluble ln water. The lnventlon use of the term "solutlon"
lncludes slurrles, suspenslons and the llke. Tetrapotasslum pyrophosphate ls freely soluble ln water and ls lnsoluble ln ethanol.
The lnventlon product does not lnclude any fluorlne-contalnlng compound or other fluorlde lon source, or guaternary ammonlum compounds. The lnventlon does not lnclude organlc acid pyrophosphates.
More preferably a mixture of trisodium monoacld pyrophosphate and tetrapotasslum pyrophosphate is used ~in a ratio to achieve the desired pH).
The maximum allowable GRAS level in the U.S. In a composition for sodlum acld pyrophosphate (SAPP) ls 2.1 weight percent and for tetrapotasslum pyrophosphate (TKPP) or . 1338179 .

tetrasodium pyrophosphate (TSPP) 1.4 weight percent in baked goods. If GRAS levels change (rise) or if higher levels are allowed by the regulatory agencies, higher levels can be used in the invention. TSPP delivers about 65.4 percent by P207, TKPP
delivers about 52.65 percent of P207 and SAPP delivers about 78.36 percent of P207.
The preferred invention coating contains trisodium monoacid pyropho~;phate and tetrapotassium pyrophosphate in a weight ratio of about: 60 to about 40.
Th~ pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5, preferably from about 3.5, most preferably 1.4 to 2.5 weight percent (based on the total composition), of P207.
A study of the àpplication of aqueous solutions of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate to the teeth of dogs by spraying for one mouth resulted in dose response data. The aqueous solutions containing 5 and 3 weight percent of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate resulted in significant reductions in tartar accumulation. The aqueous solutions containing 1.5 and 0.5 weight percent of such mixture resulted in directional trends of reductions in tartar a~cumula~tion. See also U.S. Patent No. 3,323,551.
The ratio of sodium acid pyrophosphate (SAPP) to tetrapotassium pyrophosphate (TKPP) is between 4 to 1 and 3 to 7, preferably between 7 to 3 and 1 to 1, most preferably about 3 to about 2. SAPP has a pH of 4.2 and TKPP (and TSPP) has a pH
of 10.2, so the combination of SAPP and TKPP (or TSPP) provides a resultant pH which is a balance of the pHs of the two components. The pH of the coating solution of at least one inorganic pyrophosphate salt (and baked, coated dog biscuit) is generally in the range of about 4 to about 10.5, typically from about 4.5 to about 7.5, preferably from about 5 to 7, most preferably about 5.6 to 6.1. Milk Bone has a pH of 6.1 to 6.4.
Tartar reduction is indicated to be best at neutral pH and palatability is indicated to be best at a slightly acidic pH, so the best mode contemplates a balance of such two factors in any commercial product. The coating solution application is usually conducted at a temperature of about 45 to about 140F, preferably about 60 to about 125F.
The coating solution contains a suitable surfactant. The preferred surfactant is lecithin or a modified lecithin, most preferably a modified lecithin which is in a dry form.
Preferably about 0.5 to about 1.75 weight percent of the lecithin or modified lecithin is used. The surfactant or wetting agent helps the coating material to apply over the entire surface of the dog biscuit dough pieces. The liquefied coating formulation best contains at least one suspension agent.
The preferred suspension agent is a polysaccharide gum.
`Preferably about 0.05 to 1.25 weight percent of xanthan gum is used. Xanthan gum is one of the few gums which acts as an acceptable suspension agent in the invention. Any suitable gums and mucilages can be used. Xanthan gum is preferred because it is stable over a broad range of temperature and holds the same viscosity in the liquefied coating formulation over the broad temperature range. The xanthan gum has a bodying effect so that 1338l7~

little or no separation occurs. Malto-dextrin produced by hydrolyzing corn starch is preferred. It serves as a carrier (bodying), binding agent and suspension agent and helps the appearance of the coating. It is a preferred ingredient, but any suitable dextrin can be used in its place. Other malto-dextrins can also be used for the same functions.
An adhesive or binding agent, such as, malto-dextrins, is needed in the coating slurry to help the coating material bind (adhere) to the dog biscuit when the dog biscuit is dipped in the coating slurry. Preferably about 5 to about 15 weight percent of the-dextrin or malto-dextrin is included in the coating material.
A carrier, such as, starch or a modified food starch, is included in the coating formulation. Preferably about 0.1 to about 5 weight percent of the food starch or modified food starch is included in the coating material. The food starch or modified food starch also serves to control the viscosity.
Animal fat preferably is included for flavor purposes.
Other suitable flavorants can be included, particularly salt.
The flavorants can be any dairy product flavorant, such as, milk or cheese, meat flavorants, such as, liver or beef, poultry and fish. Flavorants help provide palatability for the invention coating.
Preferably a hydrogenated vegetable oil is included in the coating formulation for sheen and to modify the melting point of the formula fats in the finished product. It also helps to prevent flaking of the coating; also the coating does not have a tacky feeling.

Any suitable colorant can be included in the coating formulation. The preferred colorant is caramel color, which also provides some flavor to the product.
The coating also incorporates sufficient water to achieve the liquefied coating composition. Amounts of the other ingredients are those which are effective to achieve their functions in the coating formulation. The preferred coating formulation, besides the inorganic pyrophosphates, contains animal fat, a surfactant, such as, a modified lecithin, polysaccharide gum, a modified food starch, flavorant, colorant, hydrogenated vegetable oil, a carrier, such as a malto-dextrin, and water.
The coating slurry can be applied to the dog biscuit dough pieces by any suitable means, such as, spraying, dipping, soaking in a container, etc. The coating slurry is applied generally at a temperature of 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180. The coating slurry has a low microbial profile at such higher temperatures.
The coated dough pieces can be baked using any suitable or conventional equipment and conditions. For example, the coated ~ough pieces can be passed into an oven such as a conventional band oven where the biscuit is baked. The conveyor belts of the oven can be coated with an edible lubricant such as a natural or synthetic cooking oil or shortening to facilitate separation from the conveyor belts of the baked coated products.
Temperatures in the range of about 300 to about 600F can be used. The baked coated biscuits can also be subjected to 13~8179 subsequent drying at temperatures of about 200 to 400F, either within the baking oven or separately, to produce the desired moisture content in the final product.
The coated, formed pieces are baked, followed by drying, to achieve a shelf stable product without the need of any moisture barrier protection. Baking and drying temperatures and times are those conventionally used in the production of a hard, dry canine biscuit. The pieces are dried to obtain a biscuit having a water activity of 0.70 or less. Typically baking temperatures and times are about 300F to about an average of 475F for about 25 minutes to about 8 minutes. Drying conditions are typically about 200 to about 325F for about 25 minutes to about 12 minutes in a forced air dryer. On a weight basis, the moisture content of the final coated biscuit product is less than or equal to 13 percent by weight, usually at least 5 weight percent, and most preferably about 8 to about 12 percent by weight, of the final biscuit at 70 percent relative humidity.
The ingredients, pH and ranges for the invention coated dough are the same for the invention coated dog biscuits. The invention product is similar in palatability to Mil ~ dog biscuits, which have been widely accepted and a commercial success for many years.
The invention product does not include any fluorine-containing compound or other fluoride ion source, or quaternary ammonium compounds. Also the invention product does not include any organic pyrophosphates.
The invention deals primarily with dogs, but has a scope of teeth-bearing non-human mammals, such as, cats.

1~38179 The invention composition is used to reduce and control tartar accumulation on canine teeth.

The following coating-baking procedure is particularly advantageous:
(a) dry blending the dry powders.
(b) adding 1/4 of the water and slurring the composition.
(c) adding remaining 3/4 of the water and mixing to form the coating formulation.
(d) heating the coating formulation to 185 to 200F with intermittent stirring (add animal fat at about 125F
during the heating).
(e) maintaining the coating formulation at 160 to 190F.
(f) apply the coating material to the unbaked dough pieces.
(g) baking the coated, unbaked dough pieces at 325F for 25 minutes.
(h) drying the baked, coated dough pieces for 25 minutes at 225F in a forced-air dryer.
The invention also includes a process for preparing raw hide containing at least one inorganic pyrophosphate compound,-comprising:
(a) subjecting raw hide to a solution containing at least one inorganic pyrophosphate compound; and (b) drying the raw hide containing said at least one inorganic pyrophosphate compound.
The invention further includes raw hide containing at least one inorganic pyrophosphate salt. The invention also includes a process for the prevention of tartar accumulation on the teeth of dogs comprising chewing and/or eating the treated raw hide.

The preferred coating formulation is:
Table 2 Ingredients Percentages Specific Ranqes Sodium acid pyrophosphate (SAPP), anhyd:rous powder, (non-leavening type) 1.73 0.25 to 5 Tetrapotassium pyrophosphate (TKPP), anhydrous powder 1.15 0.25 to 5 Salt 0.50 0.05 to 2.5 Malto-Dextrin 9.17 2 to 30 Modified Food Starch 2.00 0.1 to 10 Colorant 0.50 0.01 to 3 Flavorant 2.00 0.01 to 5 Xanthan 0.20 0.05 to 1.5 Lecithin or Modified Lecithin1.25 0.5 to 1.75 Vegetable Fat 0.50 0.1 to 3 Animal Fat 1.00 0.1 to 5 Subtotal20.00 Water (assumed completely evaporated after drying) 80.00 50 to 97 Total 100.00 1~38179 In the preparation of raw hide, the skin that is made into raw hide should not be salted: instead, it is softened with water and immersed in a dehairing solution made, for example, by combining 2-1/2 pounds of slaked caustic lime with ten gallons of water. The skin is left in the solution until the hair slips very easily, and then it is removed and rinsed in clean water.
After letting the skin drain, it is put on the fleshing beam and the hair is scraped off as well as the epidermis layer of skin under the hair. When the hair is gone, the hide is turned over and fleshed very well, removing every bit of flesh and fat.
Then the hide is soaked for a while in clean water to wash away all dirt and bits of material removed by the fleshing and dehairing operations. The hide is stretched on a frame and allowed to air dry.
More generally, hair removal can be accomplished with a saturated solution of calcium hydroxide (lime) alone or in combination with a sharpening agent, e.g., sodium sulfide or sodium sulfhydrate. Lime by itself does not dissolve the hair but only loosens it in the base of the hair follicle for easy removal by an unhairing machine. This labor-intensive apparatus scrapes the loosened hair from the surface of the skin and is ~ermed a hair-save process. Lime, by itself, requires from 5 to 7 days to loosen the hair. Because of the importance of time, a hair-burn process is more commonly used. Although sulfide at a pH greater than 11.5 can dissolve the hair in as little as 30 to 40 minutes, the usual sulfide unhairing process takes from 4 to 6 hours.

1~3817~

The dehairing scheme using ultrasonic vibration of U.S.
Patent No. 2,965,435 can be used.
The relatively brief unhairing step can be followed by the longer (4 to 16 hours) liming step. The spent unhairing liquors with the dissolved hair are drained from the hides and a fresh saturated lime solution is added. The action of lime not only loosens the hair but opens up the collagen fiber structure.
Collagen swells outside of its isoelectric point in either acid or base in 8 to 48 hours. This swelling leads to subsequent fiber separation and allows relatively rapid penetration of the inorganic pyrophosphate solution of the invention into the raw hide.
The liming step, when complete, is followed by deliming.
The hide is washed to remove soluble lime and hair particles.
At this point, the stock is at a pH of 12.5. The most widely used deliming salt is ammonium sulfate, which lowers the pH to 8 to 9.
Puering is the treatment of delimed or partially delimed skins. Bating is a similar process, generally 'synthetic' bates are used; these contain enzymes, obtained from the pancreas of animals, to which neutral deliming salts are added. Puering and ~ating assist in the removal of short hairs, lime soaps, and cementing substances in the skin, and in depleting and deliming.
As a result of this process, the stretch and pliability of the leather is increased. Puering and bating are optional in the process of preparing edible raw hide for dogs and other animals.
The invention product is dried so that it comprises a dry raw hide strip containing at least one inorganic pyrophosphate.

13~8179 The invention product should be slightly acid to near neutral.
The invention product is chewable, tough and flexible.
When chewed by dogs, the invention product cleans teeth surfaces, removes tartar (by mechanical action), and exercises and massages the gums. The pyrophosphate in the invention prevents the formation of tartar on the dog's teeth.
The inorganic pyrophosphates are anti-tartar, anti-plaque or anti-calculus agents. The invention product exhibits anti-tartar properties over its normal shelf-life. The invention product does not adversely affect canine tooth enamel.
Hides are normally prefleshed to remove excess flesh before shipping to companies that prepare raw hide therefrom. If the hides have been pre-soaked in salt, the salt can be removed by conventional methods.
Air drying is satisfactory for hides, but it must not be too slow or putrefaction may begin. If the air drying is too fast, the outer surface may become hard and dry while the inner parts still have enough moisture to support bacterial growth.
Fresh hides, if immediately removed from the animal, can be chilled and washed to remove any excess manure and then sprayed with a disinfectant. The longer the period of time that the disinfectant is effective, the longer it will be before there is any damage to the hides and the greater the distance that the hides can be shipped. One should make sure that the disinfectant is removed before or during the dehairing and/or liming steps.

1~38173 The raw hide is preferably made from cattle hides, but can be made from horse hides, calf skins, sheep skins, goat skins, kid skins, marsupial skins, buffalo hides and pig skins, for example. Fresh cattle hides contain 65 to 70 percent of water, 30 to 35 percent of dry substance, and less than 1 percent of ash. The dry substance is largely made up of the fibrous proteins, collagen, keratin, elastin and reticulin. The main components of the ash, listed in decreasing concentratLon, are phosphorus, potassium, sodium, arsenic, magnesium and calcium.
Collagen in the hides is responsible for the toughness and strength in the raw hide.
Liming is a process in which the hides or skins are immersed in solutions of milk of lime, or slaked lime, to which small amounts of sodium sulphide, ammonium salts, or sometimes enzymes may be added. The object of liming is primarily to loosen the hair, usually by destroying or loosening the epidermis: at the same time the fibrous structure becomes swollen and plumped with a partial separation of the fibres.
Lime and other alkalis combine with the natural grease in the skin to form soaps, which are removed in the subsequent bating and scudding operations. Liming may be carried out by immersing ~the pelts in pits, paddles, or drums.
In pit liming the hides or skins are placed in brick or concrete pits. The goods are immersed in lime liquor in the pits for three days, after which time either the liquor is strengthened by the addition of freshly slaked lime paste (one pit system), or the goods are transferred to a once-used lime liquor and after a further three days placed in a new liquor (three pit system), the total period being 8 to 10 days. Pit liming is laborious as the goods must be hauled frequently from the pits to permit circulation of the liquor. Mechanical devices have been devised for agitating lime liquors but have not met with general acceptance. Instead of using pits, liming in a drum is more generally favored since it reduces both time and labor.
Unhairing or dehairing is a process in which the hair is removed from the skin after it has been loosened by liming.
This may be done manually by means of a blunt-edged knife which is tilted away from the operator, so that the hair and scud are pushed or scraped off the skin. Unhairing machines, in which the hair side of the skins is brought near to a rapidly revolving cylinder fitted with a series of blunt blades, have largely superseded hand unhaiting.
Any adipose tissue remaining on the flesh side of the skin is removed, after liming, in the process of 'fleshing'. A
special knife is used for hand fleshing, but the process is usually carried out by means of a fleshing machine comprising a revolving roller fitted with sharp spiral blades.
The deliming is preferably complete. Un~ess the lime is `removed, the finished leather is hard with a brittle grain and shows discolorations. Only about 50 percent of the lime can be removed from the skin by washing in running water, the residual lime being combined with some of the free acid groups in the collagen. By treatment with inorganic acids, organic acids, or acid salts, complete removal of lime is effected.

1~38179 The hides, skins, or leather are often separated or split into two sections or layers of even thickness; the outer or grain layer, and the under or flesh layer. The splitting is usually done on a band knife splitting machine.
The prepared raw hides can be cut into strips by a cutter that exerts a scissor-like action.
The lime treatment apparently opens up the collagen fiber structure and allows relatively rapid penetration of the pyrophosphate solution into the raw hide. The pyrophosphate solution should usually contain only water and the inorganic pyrophosphate. Water-soluble flavorants, e.g., liver, beef, cheese, etc., can be included in the pyrophosphate solution.
Depending upon the desired pH of the pyrophosphate solution, an inorganic base (e.g., NaOH, KOH, CaOH, LioH, MgOH, etc.) or an inorganic acid (e.g., H2SO4' HCl, etc.) can be used to adjust the pH. Use of an acid or base has the disadvantage of resulting in unwanted non-pyrophosphate salts. Preferably the pH adjustment is done by using ratios of inorganic pyrophosphates having different pHs. The length of treatment of the raw hide with the pyrophosphate solution is one determinative factor in the degree of penetration, that is, surface, intermediate or completely.
The solvent is preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used.
The problem of the necessity of solvent removal from the treated raw hide due to toxicity is to be avoided in most cases. If a mixture of ethanol and water is used, the amount of ethanol in the mixture is generally about 5 to about 60 percent, preferably 13~8179 about 5 to about 25 percent. When one or more of the inor-ganlc pyrophosphates is not water soluble, lt may be ethanol soluble.
The invention includes the use of at least one inor-ganic pyrophosphate. Preferably the inorganic pyrophosphates are water soluble. A water insoluble pyrophosphate in a slurry may tend to deposit in the surface regions of the raw hide. The use of very fine partlcles of a water insoluble lnorganlc pyrophosphate may provlde better penetratlon lnto the interior regions of the raw hide. Water insoluble inor-ganic pyrophosphates have abrasive actlon.
The inorganic pyrophosphates are preferably alkali metal pyrophosphates. The preferred alkali metal pyrophos-phates are tetrasodium pyrophosphate and tetrapotassium pyro-phosphate. An example of a useful tetraalkali metal pyrophos-phate is tetralithium pyrophosphate. Alkaline earth metal pyrophosphates are also useful, but they are generally insol-uble ln water. Preferably the lnorganic pyrophosphates are soluble in water.
Kirk & Othmer, "Encyclopedia Of Chemical Technology", 2nd Ed., Vol. 15, (1965), pages 232 to 276, discloses a number of water-soluble and water insoluble inorganlc pyrophosphate salts.
Mn+2PnO3n+l, where M is a univalent metal, is the formula for univalent metal pyrophosphates when n is 2. The formula M'nPnO3n+1, where M' is a divalent metal, is the formula for divalent metal pyrophosphates when n is 2.
Such univalent metal pyrophosphates and divalent metal pyro-phosphates can be 133817~
used in the invention. Polypyrophosphates have the formula Mn+2PnO3n+1 or M ~ nPn3n+1' there n is 2,3,4,5..., and the oxide ratio R between the cationic oxides (M20) iand M ~ O and anionic oxides (P205) is between 1 and 2. The oxide ratio for pyrophosphate is 2.
Examples of dialkaline metal pyrophosphates are dicalcium pyrophosphate, dibarium pyrophosphate and dimagnesium pyrophosphate. Trialkali metal monoacid pyrophosphates, such as, trisodium hydrogen pyrophosphate, can be used. Monoalkali metal triacid pyrophosphates, such as, sodium trihydrogen pyrophosphate, can also be present in limited amounts. Examples of other inorganic pyrophosphates include dimanganese pyrophosphate and dizinc pyrophosphate.
Tetrasodium pyrophosphate, one part, is soluble in 13 parts of cold water and in 2.5 parts of boiling water. It is insoluble in ethanol. Dicalcium pyrophosphate is practically insoluble in water. The invention use of the term "solution"
includes slurries, suspensions and the like. Tetrapotassium pyrophosphate is freely soluble in water and is insoluble in ethanol.
The solution can also contain suitable s~rfactants or emulsifying agents. The emulsifier is best only used in minor amounts which are effective in keeping a water insoluble inorganic pyrophosphate in suspension.
The invention product does not include any fluorine-containing compound or other fluoride ion source, or quaternary ammonium compounds. The invention does not include organic acid pyrophosphates.

13~8l7~

Preferably a mixture of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate is used (in a ratio to achieve the desired pH).
Federal GRAS regulations are that the upper amount of pyrophosphate moiety, P2O7' delivered is 0.5 weight percent (based on the total composition). The maximum allowable GRAS
level in a composition for sodium acid pyrophosphate (SAPP) is 0.3 weight percent and tetrasodium pyrophosphate (TSPP) is 0.5 weight percent, such weight percentages being based on the total weight of the product. If GRAS levels change (rise) or if higher levels are allowed by the regulatory agencies, higher levels can be used in the invention.
The preferred invention solution contains trisodium monoacid pyrophosphate (SAPP) and tetrapotassium pyrophosphate in a weight ratio of about 60 to about 40.
The pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5 weight percent, preferably from 0.4 to 0.5 weight percent (based on the total composition), of P2O7.
A study of the application of aqueous solutions of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate to the teeth of dogs by spraying for one month resulted in dose response data. The aqueous solutions containing 5 and 3 weight percent of such pyrophosphate mixture resulted in significant reductions in tartar accumulation. The aqueous solutions containing 1.5 and 0.5 weight percent of such pyrophosphate mixture resulted in directional trends of reductions in tartar accumulation.

133817~

The ratio of sodium acid pyrophosphate (SAPP) to tetrapotassium pyrophosphates (TKPP) is between 0.01 to 99.99 and 99.99 to 0.01 weight percent.
The pH of the solution of at least one inorganic pyrophosphate compound (salt) is generally in the range of about 4 to about 10.5, typically from about 5 to about 8, preferably from about 5.5 to about 6.5, most preferably about 6.
The solution application usually is conducted at a temperature of about 45 to about 140F, preferably about 60 to about 110F.
The solution containing the pyrophosphate compound-is allowed to fully penetrate the raw hide or to penetrate only the surface region of the raw hide. The raw hide is in the uncut form or preferably is in strip form.
The solution can be applied to the raw hide by any suitable means, such as, spraying, soaking in a container, etc., but the preferred method is by dipping the raw hide strips in the solution. (The raw hide strips can be in long rope form; the coating applied and dried; and the rope then cut into shorter strips.) After treating the raw hide with the pyrophosphate compound, the raw hide is dried. While the treated raw hide is preferably air dried, it is also advantageous to dry the treated raw hide using applied heat, e.g., in a hot air oven (at a temperature of say 75 to 300F).
The invention product can be raw hide in any shape which can be chewed by dogs. Examples of such raw hide shapes are strips, balls made up of pieces or strips, knotted strips, bones made up of pieces of strips, curled pieces, etc. The raw hide can be that which has been molded (e.g., compressed, extruded, stamped, tabletted, etc.) and formed.
The invention deals primarily with dogs, but has a scope of teeth bearing non-human animals or mammals, such as, cats. The invention composition is used to reduce or prevent tartar accumulation on canine teeth and other non-human animal or mammal teeth.
The invention also includes a process for preparing raw hide having a coating containing at least one inorganic pyrophosphate compound, comprising:
(a) subjecting raw hide to a liquefied coating material at least one inorganic pyrophosphate compound; thereby, forming a coating of such liquefied coating material on the raw hide; and (b) drying the raw hide having a coating containing said at least one inorganic pyrophosphate compound.
The invention further includes raw hide having a coating containing at least one inorganic pyrophosphate salt. The invention also include a process for the prevention of tartar accumulation on the teeth of dogs comprising chewing and/or eating the raw hide having a coating containing at least one ~norganic pyrophosphate.
The above information on the preparation of raw hide is applicable here.
When the invention liquefied coating material is applied to the raw hide, its consistency, viscosity, solids content, etc., keeps it primarily on the surface of the raw hide. Some of the liquefied coating material will seep into the surface regions of the raw hide, thereby, helping to anchor or adhere the coating to the raw hide once it is dried.
The invention product is dried so that it comprises a dry raw hide strip having at least one inorganic pyrophosphate.
Dogs prefer the coated product over uncoated raw hide, apparently are an individual dogs' preference. Dogs appear to attempt to gnaw the coating off of the coated raw hide after the initial smell and taste. After the coating is gone sometimes the raw hide is left uneaten. The invention product is very effective in reducing the accumulation of tartar on the teeth of dogs.
The invention product should be slightly acid to near neutral.
The invention product is chewable, tough and flexible.
When chewed by dogs, the invention product cleans teeth surfaces, removes tartar (by mechanical action), and exercises and massages the gums. The pyrophosphate in the invention prevents the formation of tartar on the dog's teeth.
The inorganic pyrophosphates are anti-tartar, anti-plaque or anti-calculus agents. The invention product exhibits anti-tartar properties over its normal shelf-iife.
The invention further includes a coating comprised of malto-dextrin, food starch or modified food starch, optional colorant, optional flavorant for animals or humans suitable polysaccharide gum (preferably xanthan gum), surfactant (preferably lecithin or modified lecithin), vegetable fat or animal fat). The coating can be used on baked dough.

The raw hide is preferably made from cattle hides, but can be made from horse hides, calf skins, sheep skins, goat skins, kid skins, marsupial skins, buffalo hides and pig skins, for example. Fresh cattle hides contain 65 to 70 percent of water, 30 to 35 percent of dry substance, and less than 1 percent of ash. The dry substance is largely made up of the fibrous proteins, collagen, keratin, elastin, and reticulin. The main components of the ash, listed in decreasing concentration, are phosphorus, potassium, sodium, arsenic, magnesium, and calcium.
Collagen in the hides is responsible for the toughness and strength in the raw hide.
The deliming is preferably complete. Unless the lime is removed, the finished leather is hard with a brittle grain and shows discolorations. Only about 50 percent of the lime can be removed from the skin by washing in running water, the residual lime being combined with some of the free acid groups in the collagen. By treatment with inorganic acids, organic acids, or acid salts complete removal of lime is effected.
The hides, skins, or leather are often separated or split into two sections or layers of even thickness; the outer or grain layer, and the under or flesh layer. Tfie splitting is usually done on a band knife splitting machine.
The prepared raw hides can be cut into strips by a cutter that exerts a scissor-like action.
The solvent used in the coating is preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used. The problem of the necessity of solvent removal from the treated raw hide due to toxicity is to 1~3817~

be avolded ln most cases. If a mlxture of ethanol and water ls used, the amount of ethanol ln the mlxture ls generally about 5 to about 60 percent, preferably about 5 to about 25 percent. When one or more of the lnorganlc pyrophosphates ls not water soluble, lt may be ethanol soluble.
The invention lncludes the use of at least one lnor-ganic pyrophosphate. Preferably the lnorganlc pyrophosphates are water soluble. A water insoluble lnorganlc pyrophos-phate(s) can be used by ltself or ln a mlxture wlth at least one water soluble lnorganlc pyrophosphate. Water lnsoluble lngredlents result ln a slurry. The use of very flne par-tlcles of a water lnsoluble lnorganlc pyrophosphate provides better suspenslon ln the coatlng formulatlon. Water insoluble lnorganlc pyrophosphates have abraslve actlon.
The lnorganlc pyrophosphates are preferably alkall metal pyrophosphates. The preferred alkali metal pyrophos-phates are tetrasodlum pyrophosphate and tetrapotasslum pyrophosphate. An example of a useful tetraalkall metal pyrophosphate ls tetralithlum pyrophosphate. Alkallne earth metal pyrophosphates are also useful, but they are generally lnsoluble ln water. Preferably the lnorganlc pyrophosphates are soluble ln water.
Kirk & Othmer, "Encyclopedla Of Chemlcal Technology", 2nd Ed., Vol. 15, (1965), page 232 to 276, dlscloses a number of water-soluble and water lnsoluble lnorganlc pyrophosphate salts.

Examples of dialkaline metal pyrophosphates are dicalcium pyrophosphate, dibarium pyrophosphate, and (dimagnesium pyrophosphate. Trialkali metal monoacid pyrophosphates, such as, trisodium hydrogen pyrophosphate, can be used. Monoalkali metal triacid pyrophosphates, such as, sodium trihydrogen pyrophosphate, can also be present in limited amounts. Examples of other inorganic pyrophosphates include dimanganese pyrophosphate and dizinc pyrophosphate.
The formula Mn+2PnO3n+1l where M is a univalent metal, is the formula for univalent metal pyrophosphates when n is 2. The formula M'nPnO3n+,, where M' is a divalent metal, is the formula for divalent metal pyrophosphates when n is 2. Such univalent metal pyrophosphates and divalent metal pyrophosphates can be used in the invention. Polyphosphates have the formula Mn+2PnO3n+1' or M~nPnO3n+1' where n is 2,3,4,5,..., and the oxide ratio R between the cationic oxides and anionic oxides (P205) is between 1 and 2. The oxide ratio for pyrophosphate is 2.
Tetrasodium pyrophosphate, one part, is soluble in 13 parts of cold water and in 2.5 parts of boiling water. It is insoluble in ethanol. Dicalcium pyrophosphate is practically insoluble in water. The invention use of the term "solution"

includes slurries, suspensions and the like. Tetrapotassium pyrophosphate is freely soluble in water and is insoluble in ethanol.
The invention product does not include any fluorine-containing compound or other fluoride ion source, or quaternary ammonium compounds. The invention does not include organic acid pyrophosphates.

1~38173 Preferably a mixture of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate is used (in a ratio to achieve the desired pH).
Federal GRAS regulations are that the upper amount of pyrophosphate moiety, P207, delivered is 0.5 weight percent (based on the total composition). The maximum allowable GRAS
level in a composition for sodium acid pyrophosphate (SAPP) is 0.3 weight percent and tetrasodium pyrophosphate (TSPP) is 0.5 weight percent, such weight percentages being based on the total weight of the product.
The preferred invention solution contains trisodium monoacid pyrophosphate (SAPP) and tetrapotassium pyrophosphate in a weight ratio of about 60 to about 40.
The pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5, preferably from 0.4 to 0.5 weight percent (based on the total composition) of P207.
A study of the application of aqueous solutions of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate to the teeth of dogs by spraying for one month resulted in does response data. The aqueous solutions containing 5 and 3 weight percent of such pyrophosphate mixture ~esulted in significant reduction sin tartar accumulation. The aqueous solutions containing 1.5 and 0.5 weight percent resulted of such pyrophosphate mixture in directional trends of reductions in tartar accumulation.
The ratio of sodium acid pyrophosphate (SAPP) to tetrapotassium pyrophosphate (TKPP) is between 0.01 to 99.99 weight percent and 99.99 to 0.01 weight percent.

13~817~
The pH of the solution of at least one inorganic pyrophosphate compound (salt) is generally in the range of about 4 to about 10.5, typically from about 5 to about 8, preferably from about 5.5 to about 6.5, most preferably about 6.
The solution application is usually conducted at a temperature of about 45 to about 200F, preferably about 60 to about 190F.
The solution can also contain suitable surfactants or emulsifying agents. The preferred surfactant is lecithin or a modified lecithin, most preferably a modified lecithin which is in a dry form. Preferably about 0.5 to about 1.75 weight percent of the lecithin or modified lecithin is used. The surfactant or wetting agent helps the coating material to apply over the entire surface of the raw hide strips.
The liquefied coating formulation best contains at least one suspension agent. The preferred suspension agent is a polysaccharide gum. Preferably about 0.05 to 1.25 weight percent of xanthan gum is used. Xanthan gum is one of the few gums which acts as an acceptable suspension agent in the invention. Other suitable gums and mucilages can be used.
Xanthan gum is preferred because it is stable over a broad range of temperature and holds the same viscosity in the liquefied coating formulation over the broad temperature range. The xanthan gum has a bodying effect so that little or no separation occurs.
Malto-dextrin produced by hydrolyzing corn starch is preferred. It serves as a carrier (bodying), binding agent and 1:~38179 suspension agent and helps the appearance of the coating. Other malto-dextrins can also be used for the same functions.
An adhesive or binding agent, such as, malto-dextrins, is needed in the coating slurry to help the coating material bind (adhere) to the raw hide when the raw hide is dipped in the coating slurry. Preferably about 5 to about 15 weight percent of the malto-dextrin is included in the coating material.
A carrier, such as, starch or a modified food starch, is included in the coating formulation. Preferably about 0.1 to about 5 weight percent of the food starch or modified food starch is included in the coating material. The food starch or modified food starch also serves to control the viscosity.
Animal fat preferably is included for flavor purposes.
Other suitable flavorants can be included, particularly salt.
The flavorants can be any dairy product flavorant, such as, milk or cheese, meat flavorants, such as, liver or beef, poultry and fish. Flavorants help provide palatability for the invention coating.
Preferably a hydrogenated vegetable oil, is included in the coating formulation for sheen and to modify the melting point of the formula fats in the finished product. It also helps to prevent flaking of the coating; also the coating does not have a tacky feeling.
Any suitable colorant can be included in the coating formulation. The preferred colorant is caramel color, which also provides some flavor to the product.
The coating also incorporates sufficient water to achieve the liquefied coating composition. Amounts of other ingredients 133~17~

are those which are effective to achieve their functions in the coating formulation.
The preferred coating formulation, besides the inorganic pyrophosphates, contains animal fat, a surfactant, such as, a modified lethicin, polysaccharide gum, a modified food starch, flavorant, colorant, hydrogenated vegetable oil, and a carrier, such as malto-dextrin and water.
The coating formulation should be viscous enough so that the coating formulation generally only coats the surface regions of the raw hide. The presence of coating in the surface regions of the raw hide helps to anchor the resultant coating and to prevent the coating from easily being separated from the raw hide during handling and shipping and the coating is strictly a surface phenomena on the raw hide.
The coating slurry can be applied to the raw hide by any suitable means, such as, spraying, soaking in a container, etc., but the preferred method is by dipping the raw hide strips in the solution. (The raw hide could be in long rope into shorter strips.) The coating slurry is applied generally at a temperature of 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180. The coating slurry ~as a low microbial profile at such higher temperatures.
After treating the raw hide with the pyrophosphate compound slurry, the raw hide is dried. While the treated raw hide is preferably air dried, it is also advantageous to air oven (at a temperature of say 75 to 300F).
The invention product can be raw hide in any shape which can be chewed by dogs. Examples of such raw hide shapes are 133~17~
strips, balls made up of pieces or strips, knotted strips, bones made up of pieces or strips, curled pieces, etc. The raw hide can be that which has been molded (e.g., compressed, extruded, stamped, tabletted, etc.) and formed.
The invention deals primarily with dogs, but has a scope of teeth bearing non-human animals or mammals, such as, cats. The invention composition is used to reduce or prevent tartar accumulation on canine teeth and other non-human animal or mammal teeth.

The preferred coating formulation is:
Table 3 Ingredients Percentages Specific Ranges Sodium acid pyrophosphate (SAPP), anhydrous powder, (non-leavening type) 1.73 0.25 to 5 Tetrapotassium pyrophosphate (TKPP), anhydrous powder 1.15 0.25 to 5 Salt 0.50 0.05 to 2.5 Malto-Dextrin 9.17 2 to 30 Modified Food Starch 2.00 0.1 to 10 Colorant 0.50 0.01 to 3 Flavorant 2.00 0.01 to 5 Xanthan 0.20 0.05 to 1.5 Lecithin or Modified Lecithin1.25 0.5 to 1.75 Vegetable Fat 0.50 0.1 to 3 Animal Fat 1.00 0.1 to 5 Subtotal20.00 Water 80.00 50 to 97 Total 100.00 133817~
The invention includes a viscous, liquefied coating formulation comprised of a surfactant, an effective polysaccharide gum, a binding agent, a starch carrier, a hydrogenated vegetable oil. A preferred coating formulation contains a surfactant, such as, lecithin or modified lecithin, xanthan gum (or other suitable polysaccharide gum), a starch or modified food starch, hydrogenated vegetable oil and a binding agent, such as, malto-dextrin, and water. Optional ingredients humectant, preferably propylene glycol, can be used in the coating formulation. The invention coating can, but does not have to, contain at least one inorganic pyrophosphate salt.
The invention coating can be applied to any suitable human or animal food, such as, non-human animals, e.g., cats and dogs. The invention coating is preferably applied to baked dog biscuits and then both are dried.
The liquefied coating formulation best contains at least one suspension agent. The preferred suspension agent is a polysaccharide gum, most preferably xanthan gum. Preferably about 0.05 to 1.25 weight percent of polysacchaEide gum (xanthan gum) is used. Xanthan gum is one of the few gums which acts as an acceptable suspension agent in the invention.' The xanthan gum is "an excellent agent for controlling the bodying effect, as it is stable over a broad temperature range, i.e., it holds the same viscosity over a large temperature range without any separation of the coating ingredients. Other suitable gums and mucilages can be used.
Malto-dextrin produced by hydrolyzing corn starch is preferred: it serves as a carrier (bodying), binding agent and suspension agent and helps the appearance of the coating; and it is a preferred ingredient. Other malto-dextrins can also be used.
An adhesive or binding agent, such as, malto-dextrins, is needed in the coating slurry to help the coating material bind (adhere) to the raw hide when the raw hide is dipped in the coating slurry. Preferably about 5 to about 15 weight percent of the malto-dextrin is included in the coating material.
A carrier, such as, starch or a modified food starch, is included in the coating formulation. Preferably about 0.1 to about 5 weight percent of the food starch or modified food starch is included in the coating material. The food starch or modified food starch also serves to control the viscosity.
Animal fat preferably is included for flavor purposes.
Other suitable flavorants can be used or included, particularly salt. The flavorants can be any dairy product flavorant, such as milk or cheese, meat flavorants, such as, liver or beef, poultry and fish. Flavorants help provide palatability for the invention coating.
Preferably a hydrogenated vegetable oil is included in the coating formulation for sheen and to modify the melting point of the formula fats in the finished product. It also helps to prevent flaking of the coating; also the coating does not have a tacky feeling.
Any suitable colorant can be included in the coating formulation. The preferred is caramel color which also provides some flavor to the product.
The coating also incorporates sufficient water to achieve the liquefied coating composition. Amounts of the other ingredients 1~38173 are those which are effective to achleve thelr functlons in the coatlng formulatlon.
A preferred coatlng formulatlon for dog blscults contaln water, anlmal fat, a surfactant, such as, a modifled leclthln, xanthan gum, a modlfled food starch, flavorant, colorant, hydrogenated vegetable oll and a carrler, such as a malto-dextrln.
Another preferred embodiment for the invention coat-ing for dog blscults and ranges of the lngredlents of the coating is:
Percentages Inqredients Specific Ranqes Salt 0.50 0.05 to 2.5 Malto-Dextrin 9.17 2 to 30 Modlfled Food Starch 2.00 0.1 to 10 Colorant 0.50 0.01 to 3 Flavorant 2.00 0.01 to 5 Xanthan 0.20 0.05 to 1.5 Leclthin or Modlfled Leclthln 1.25 0.5 to 1.75 Vegetable Fat 0.50 0.1 to 3 Anlmal Fat 1.00 0.1 to 5 Subtotal 20.00 Water 80.00 50 to 97 Total 100.00 The lnventlon coating formulation can contain a humectant, such as, corn syrup, sugar and polyalcohols, such as, propylene glycol (preferred), sorbitol and glycerin.
The lnvention product does not lnclude any fluorlne 133817~

contalnlng compound or other fluorlde lon source, or guaternary ammonlum compounds.
The lnventlon coatlng can be applled, for example, to any sultable dog food, such as, dog blscuits, whlch can be made from any sultable dough comprlslng at least flour, meal, fat and water can be employed for the product. For lnstance, when the deslred product ls a canine biscult, a conventlonal dough for dog blscults can be used, optlonally contalnlng dlscrete partlcles of meat and/or meat byproducts or farlna-ceous material. Such doughs typcially contain fat solids.Examples of suitable doughs for the production of hard dog blscults are disclosed in U.S. Patent No. 4,454,163, and sultable doughs for the productlon of soft dog blscults (con-talnlng humectant to control water actlvlty) are dlsclosed ln U.S. Patent No. 4,454,164. Partlculate protelnaceous par-tlcles, such as partlcles of meat, texturlzed vegetable pro-teln and/or meat byproducts can be lncorporated to add flavor to the blscults and texturlze the surface. Partlculate farl-naceous materlals such as bran partlcles can also be employed to te~turize the lnterlor and/or surface of the blscults and to provlde other useful propertles to the product. A dough found to produce blscults hlghly palatable to dogs lncludes suitable proportlons of wheat flour, wheat meal, soybean meal, meat and bone meal, anlmal fat and natural flavors ln admlx-ture wlth water. The meal used ln the doughs sultable for productlon of blscults useful ln the lnventlon can comprlse meat and/or bone and/or vegetable matter lncludlng farlnaceous materlals, materlals prepared from legumes such as bean and peas, tuberous materlals such as potato meal, and the like.
The meals can be finely or coarsely ground as desired for the texture. Flours made from any suitable farinaceous material can be used.
The doughs generally have a water actlvity of about 0.90 and above upon completlon of mixing of the dough lngredi-ents. A suitable dough contalns farlnaceous materlal, an edlble oil, an antioxidant, an antimycotlc, salt, animal fat, added vltamlns and minerals, such as those disclosed in U.S.
Patent No. 4,229,485, column 5, llnes 7 to 57.
The composltlons of the lnventlon also preferably contain at least one animal-derived proteinaceous meal such as meat meal, bone meal and fish meal. A good biscuit dough for producing the biscuits of the inventlon contalns about 50 to 60 percent by weight of wheat flour, about 5 to 10 percent by welght of soybean meal, about 3 to 10 percent by welght of meat meal and bone meal, about 1 to 5 percent of wheat meal, about 1 to 5 percent of anlmal fat preserved wlth BHA, about 20 to 30 percent by weight of water, and about 2 to 5 percent by weight of natural flavors, vitamln and mineral preblend, and acldulant.
The dog blscult doughs can contaln a softenlng agent.
Any sultable softenlng agent can be used. The preferred humectant ls propylene glycol. Examples of other sultable humectants are corn syrup, sugar and polyalcohols, such as, sorbitol and glycerin. Any suitable humectant known ln the art can be used.
The dough ingredlents are generally mlxed at a tem-perature of about 45 to about 140F, preferably about 60 to about 125F.
The dog biscult dough for the outer portlon and the lnner portion can be mlxed uslng any sultable or conventlonal equlpment. For example, the mlxlng can be at 20 to 100 rpm.
For example, a - 77a -1~8179 dry blending step can be done typically at room temperature for a period of time of about 3 minutes to about 20 minutes. The dry-blended mixture can then be mixed with the hot water to form a first stage dough. The water which can be admixed with the dry-blended mixture is typically at a temperature of about 65 to about 150F. The hot water can be added, with mixing, over a period of time of about 3 minutes to about 6 minutes to form the first stage dough. Then, the fat portion of the biscuit dough can be admixed with the first stage dough to form the final stage dough. The fat portion can be added at a temperature at which it is at least fluid, typically at about 100 to about 150F. The fat portion can be mixed for a period of time which is sufficient to form a dough whose homogeneity is visually apparent. A
typically final mixing time is about 3 to about 5 minutes.
Preparation of the dough is achieved at about atmospheric pressure with mixing of the components being conveniently achieved in an upright sigma blade mixer or othef bakery-type mixers. The various ingredients can be added over a period of time or in a one-shot manner according to the above order of addition.
However, melted fat and water can be added simultaneously and mixed for 6 to 10 minutes.
The dough can be formed into dough pieces using any suitable or conventional manner, such as, by extrusion, molding, stamping or cutting. Any suitable dog biscuit shapes can be used, such as, bone-shaped canine biscuts. Holes can be formed in the dog biscuits to facilitate the escape of moisture during baking, cooking and/or drying.

The dog biscuit dough pieces can be baked using any suitable biscuit dough pieces can be passed into an oven such as a conventional band oven where the biscuits are baked. The conveyor belts of the oven can be coated with an edible lubricant such as a natural or synthetic cooking oil or shortening to facilitate separation from the conveyor belts of the baked products.
Temperatures in the range of about 300 to about 600F can be used.
The invention coating can be applied to the dog biscuit dough pieces before baking followed by baking at a low baking temperature of, say, about 300 to about 310F. It is preferable to apply the invention coating after the dog biscuit dough pieces have been baked.
The baked dog biscuits can also be subjected to subsequent drying at temperatures of about 200 to 400F (e.g., for 25 to 12 mintues), either within the baking oven or separately, to produce the desired moisture content. If dealing with coating dog biscuits which have been baked with the coating on the dog @iscuits, the baked, coated dog biscuits should not be dried at a temperature at above about 300F. Drying is usually done at a temperature of about 75 to 300F. to achieve the desired `moistute content (about 5 to 13 weight percent).
The invention coating is preferably applied to baked dog biscuits. The coating is preferably applied to the baked dog biscuits in the form of a liquefied coating formulation by any encompass all or part of the baked dog biscuits.
The coating formulation usually is viscous enough so that the coating formulation generally only coats the surface regions of the baked dog biscuits. The presence of coating in the sutface regions of the baked dog biscuits helps to anchor the resultant coating and to prevent the coating from easily being shipping.
The coating slurry can be applid to the baked dog biscuits by any suitable maens, such as, spraying, dipping, etc. The coating slurry is applied generally at a temperature of 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180F, (the baked dog biscuits best having been cooled, of allowed to cool, to less than 200F). The coating slurry has a low microbial profile at such higher temperatures.
After treating the baked dog biscuits with the invention coating slurry, the coated baked dog biscuits are dried. While the coated, baked dog biscuits are preferably air dired, it is also advantageous to dry the coated animal food using applied heat, e.g., in a hot air oven at a temperature of say 75 to 300F
(typically 250F for 20 minutes). The coated dog biscuits of 0.70 or less. On a weight basis, the moisture content of the final coated biscuit product is less than or equal to about 15 percent by weight and preferably about 10 to 12 percent by weight of the final biscuit at 70 percent relative humidity. The coated dog biscuits are shelf stable.
The animal food within the scope of this invention needs to have a sufficient integrity to not fall apart during processing and handling, especially, so that the coating can be applied, dried/baked, etc., without losing its integrity or cracking. The animal food is best in the form of pieces or the like, such as, kibbles, biscuits, snacks, etc. The animal food pieces can be made by any suitable forming means, such as, extruding, molding, stamplng, etc. The invention composition is used to reduce and control tartar accumulation on canlne teeth.
The animal food can be the dog food disclosed in commonly-owned, U.S. Patent No. 4,904,494, flled on September 9, 1988, entitled "Chewy Dog Snacks". A chewy, seml-plastlc, non-extruded, non-porous, microblologically-stable dog food which includes 12 to about 30 weight percent, based upon the total weight of the dog food, of gelatin; at least one acidulant; at least one cereal starch-contalnlng textural agent; at least one release agent; at least one taste agent; at least one sugar; salt; and added water. The dog food ls in a molded form. The dog food has a pH of about 3 to

5, and has a moisture content of about 10 to 25 weight per-cent, based on the welght of the dog food. The process for preparing the dog food lncludes (a) mixing the dry components and liquid components with low speed agltatlon and contlnulng the mlxlng untll a dough ls obtained; (b) forming the dough by molding or rotary moldlng into molded snack or biscuit; (c) conditioning the molded dough at 185 to 200F for about 7 to 8 minutes; and (d) packaglng the molded dog snack or blscuit in a protective package.
The invention also involves an anlmal or dog food, such as, a dog blscuit, having a soft, edible center whlch contalns at least one inorganic pyrophosphate. The center ls made soft by the lnclusion of a softening agent, such as, at least one humectant. The preferred humectant ls propylene glycol. The animal food reduces or prevents the accumulatlon of tartar on the animal's teeth.

The invention also involves animal foods, such as, dog foods, having a coating containing at least an inorganic pyrophosphate.
The coated animal food reduces or prevents the accumulation of tartar on the animal's teeth.
The invention also involves swabs, gauze and other like materials having absorbed/adsorbed therein and/or thereon a solution containing at least one inorganic pyrophosphate. The treated swab or treated gauze reduces or prevents the accumulation of tartar on the animal's teeth.
The invention further involves swabs, gauze or other like materials having thereon and/or therein a coating containing at least one inorganic pyrophosphate. The coated swab or coated gauze reduces or prevents the accumulation of tartar on the animal's teeth.
The invention involves meat jerky, such as, beef jerky, having absorbed/adsorbed therein and/or thereon a solution containing at least one inorganic pyrophosphate. The treated meat jerky reduces or prevents the accumulation of tartar on the animal's teeth.
The invention involves meat jerky, such as, beef jerky, having a coating therein and/or thereon a coating containing at least one inorganic pyrophosphate. The treated meat jerky reduces or prevents or reduces the accumulation of tartar on the animal's teeth.
The invention still further involves a process of preventing or reducing tartar accumulation on the teeth of an animal, comprising:

(a) spraying an aqueous solutlon containlng at least one lnorganlc pyrophosphate onto an anlmal food; and (b) havlng an anlmal consume the treated anlmal food.
The lnventlon deals prlmarlly wlth dogs, but has a scope of teeth bearlng non-human mammals and other anlmals, such as, cats and dogs.
The lnventlon lnvolves a dog food, such as, dog blscuits, havlng a soft center contalnlng at least one lnor-ganlc pyrophosphate. The center ls softer than the rest ofthe dog blscult, whlch can be a soft or hard dog blscult. The center ls made soft by the lncluslon of at least one softenlng agent, such as, at least one humectant.
The outer portlon of the dog food, such as, dog blscults, can be made from any sultable dog food dough, such as, sultable dog blscult dough. Any suitable dough comprising at least one flour, meal, fat and water can be employed for the product. For instance, when the desired product is a canlne blscult, a conventlonal dough for dog blscults can be used, optlonally contalnlng dlscrete particles of meat and/or meat byproducts or farinaceous material. Such doughs typical-ly contain fat solids. Examples of suitable doughs for the production of hard dog biscuits are disclosed in U.S. Patent No. 4,454,163, and sultable doughs for the productlon of soft dog biscuits (containlng humectant to control water actlvity) are dlsclosed in U.S. Patent No. 4,454,164. Particulate protelnaceous particles, such as particles of meat, texturized vegetable protein and/or meat byproducts can be incorporated to add flavor to the biscuits and texturize the surface.

Particulate farinaceous materials such as bran particles can also be employed to texturlze the interior and/or surface of the biscuits and to provide other useful properties to the product. A dough found to produce biscuits highly palatable to dogs includes suitable proportions of wheat flour, wheat meal, soybean meal, meat and bone meal, animal fat and natural flavors in admixture with water. The meal used in the doughs suitable for productlon of blscuits useful in the lnventlon can comprise meat and/or bone and/or vegetable matter includ-ing farinaceous materlals, materlals prepared from legumes such as beans and peas, tuberous materials such as potato meal, and the llke. The meals can be flnely or coarsely ground as desired for the texture. Flours made from any suit-able farinaceous material can be used.
The doughs generally have a water actlvlty of about 0.90 and above upon completlon of mlxlng of the dough lngredl-ents. A sultable dough contalns farlnaceous material, an edible oil, an antloxldant, an antimycotic, salt, anlmal fat, added vltamins and minerals, such as those disclosed in U.S.
Patent No. 4,229,485, column 5, llnes 7 to 57.
The composltlons of the invention also preferably contain at least one animal-derived proteinaceous meal such as meat meal, bone meal and fish meal. A good blscuit dough for produclng the blscuits of the invention contalns about 50 to 60 percent by weight wheat flour, about 5 to 10 percent by welght soybean meal, about 3 to 10 percent by welght meat and bone meal, about 1 to 5 percent wheat meal, about 1 to 5 percent anlmal fat preserved wlth BHA, about 20 to 30 percent by weight water, and about 2 to 5 percent by weight of natural flavors, vitamin and mineral preblend, and acidulant.
The soft center portion of the dog biscuit contains a softening agent if it is made from a dog biscuit dough. Any suitable softening agent can be used. The preferred humectant is propylene glycol. Examples of other suitable humectants are corn syrup, sugar and polyalcohols, such as, sorbitol and glycerin.
Any suitable humectant known in the art can be used.
If the softening agent is used in the outer portion of the dog biscuit, more of a softening agent should be used in the central portion to make it softer than the outer portion.
The solvent used in preparing the dog biscuit dough for the center portion is most preferably water, but other non-toxic, edible solvents, such as, ethanol or ethanol/water, can be used.
The problem of the necessityof solvent removal from the dough due to toxicity is to be avoided. If a mixture of ethanol and water is used, the amount of ethanol in the mixture is generally about 5 to 60 percent, preferably about 5 to about 25 percent. when one or more of the inorganic pyrophosphates is not water soluble, it may be ethanol soluble. It may be necessary to use a non-aqueous solvent, or mixture of water therewith, to incorporate the `inorganic pyrophosphate.
The invention includes the use of at least one inorganic pyrophosphate. Preferably the inorganic Pyrophosphate(s) is water soluble. A mixture of pyrophosphates can be used to provide a desired pH. Water-insoluble or difficulty soluble inorganic pyrophosphates can be used.

The pH of the dough can be adiusted uslng an inor-ganlc base (e.g., KOH, NaOH, CaOH, LiOH, MgOH, etc.) or an inorganic base (e.g., H2SO4 HCl, etc.), but this approach has the disadvantages of possibly causlng a mlsbalance or overabundance of one or more chemical entities and posslbly lntroduclng unwanted salts.
Generally 0.1 to 10 weight percent, preferably about 0.5 to about 3.5 weight percent and most preferably about 1.4 to about 2.5 weight percent of inorganic pyrophosphate is used.
When a mixture of tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate ln aqueous solutlon at the 5 welght percent level was incorporated in dog biscuit dough, there was reduced dough gluten development, the dog blscuits were bleached (whitish) and crumbly, and the dog blscuits were softer (a hardness problem) than the control dog biscuits. At the level of 3 weight percent of a mixture of tetrasodlum pyrophosphate and sodlum acid pyrophosphate, the same problems occurred, but less severely. The addltlon of the inorganic pyrophosphates in dry form to the dry ingredients in the dough preparation basically eliminated the above problems. It was also found that better results were secured by using the lnorganlc phosphates in powder form as opposed to granular form.
The lnorganlc pyrophosphates are preferably alkali metal pyrophosphates. The preferred alkali metal pyrophos-phates are tetrasodlum pyrophosphate and tetrapotasslum pyro-phosphate. An example of a useful tetraalkall metal pyrophos-I) phate ls tetrallthlum pyrophosphate. Alkallne earth metal pyrophosphates are also useful, but they are generally lnsol-uble ln water. Preferably, the lnorganlc pyrophosphates are soluble ln water.

- 86a -D

Examples of dialkaline metal pyrophosphates are dicalcium pyrophosphate, dibarium pyrophosphate and dimagnesium pyrophosphate. Trialkali metal monoacid pyrophosphates, such as, trisodium hydrogen pyrophosphate, can be used. Monoalkali metal triacid pyrophosphates, such as, disodium trihydrogen pyrophosphate, can also be present in limited amounts. Examples of other inorganic pyrophosphates include manganese pyrophosphate and dizinc pyrophosphate.
Tetrasodium pyrophosphate, one part, is soluble in 13 parts of cold water and in 2.5 parts of boiling water. It is insoluble in ethanol. Dicalcium pyrophosphate is practically insoluble in water. The invention use of the term "solution" includes solutions, slurries, suspensions and the like. Tetrapotassium pyrophosphate is freely soluble in water and is insoluble in ethanol.
Most preferably a mixture of sodium acid pyrophosphate and tetrapotassium pyrophosphate is used (in a ratio to achieve the desired pH).
The maximum allowable GRAS level in a composition for sodium acid pyrophosphate (SAPP) is 2.1 weight percent and tetrapotassium pyrophosphate (TKPP) is 1.4 weight percent in baked goods. If ~RAS levels change (rise) or if higher levels are allowed by the regulatory agencies, higher levels can be used in the invention.
TKPP delivers approximately 52.65 percent of P207; SAPP delivers about 78.36 percent of P207; and TSPP delivers about 65.4 percent of P207-The most preferred invention dough contains trisodiummonoacid pyrophosphate (that is, sodium acid pyrophosphate or 133817~

SAPP) and tetrapotassium pyrophosphate in a weight ratio of about 60 to 40.
The pyrophosphate(s) is used in sufficient amount to deliver generally from about 0.1 to about 5, preferably from about 0.5 to about 3.5, most preferably 1.4 to 2.5 weight percent (based on the total composition), of P2O7.
A study of the application of aqueous solutions of a mixture of tetrasodium pyrophosphate and sodium acid pyrophosphate to the teeth of dogs by spraying for one month resulted in dose response data. The aqueous solutions containing S and 3 weight percent of a mixture tetrasodium pyrophosphate and sodium acid pyrophosphate resulted in significant reductions in tartar accumulation. The aqueous solutions containing 1.5 and 0.5 weight percent of a mixture of sodium acid pyrophosphate and tetrasodium pyrophosphate resulted in directional trends of reductions in tartar accumulation. See also U.S. Patent No. 3,323,551.
The ratio of sodium acid pyrophosphate (SAPP) to tetrapotassium pyrophosphate (TKPP) is generally between 4 to 1 and 3 to 7, preferably between 7 to 3 and 1 to 1, most preferably about 3 to about 2. SAPP has a pH of 4.2 and TKPP (and TSPP) has a pH of 10.2, so the combination of SAPP and TKPP (or TSPP) provides a resultant pH which is a balance of the pHs of the two components.
The pH of the dough of the inner portion containing at least one inorganic pyrophosphate compound (salt) is generally in the range of about 4 to about 10.5, typically from about 4.5 to about 7.5, preferably from about 5 to about 7, most preferably between about 5.6 dog biscuit has a pH of 6.1 and about 6.1. Milk Bone~

dog biscuit has a pH of 6.1 to 6.4. Tartar reduction is indicated to be best at a neutral pH and palatability is indicated to be best at a slightly acidic pH, so the best mode contemplates a balance of such two factors in any commercial product.
The coating solution application is usually conducted at a temperature of about 45 to about 140F, preferably about 60 to about 12SF.
The dog biscuit dough for the outer portion and the inner portion can be mixed using any suitable or conventional equipment.
For example, the mixing can be at 20 to 100 rpm. For example, a dry blending step (dries and the inorganic pyrophosphates) can be done typically at room temperature for a period of time of about 3 minutes to about 20 minutes. The dry-blended mixture can then be mixed with the hot water to form a first stage dough. The water which can be admixed with the dry-blended mixture is typically at a temperature of about 65 to about 150F. The hot water can be added, with mixing, over a period of time of about 3 minutes to about 6 minutes to form the first stage dough. Then, the fat portion of the biscuit dough can be admixed with the first stage dough to form the final stage dough. The fat portion can be added at a temperature at which it is at least fluid, typically at about 100 to about 150F. The fat portion can be mixed for a period of time which is sufficient to form a dough whose homogeneity is visually apparent. A typically final mixing time is about 3 to about S minutes.
If there are machinability and dough structure property problems with the center portion dough, the addition of water should solve such problems. If the use of the higher water levels 1~817~

caused the dough to be so sticky as to cause problems in a sigma or rotary mixer (but normally not a significant problem in a continuous mixer). The addition of more tallow to the dog biscuit dough should assist in more effective mixing and help to keep the dough from being so sticky that it clings to a rotary molder.
Preferably the tallow level is about 2.6 to about 3.1 weight percent (most preferably about 2.85 weight percent), as opposed to a tallow level of about 5 dog biscuits. Also, 2.46 weight percent in Milk Bon ~ the tallow provides a taste which dogs like.
Formation of the dough is achieved at about atmospheric pressure with mixing of the components being conveniently achieved in an upright sigma blade mixer or other bakery-type mixers. The various ingredients can be added over a period of time or in a one-shot manner according to the above order of addition.
However, melted fat and water can be added simultaneously and mixed for 6 to 10 minutes.
The center portion of the dog biscuit can also be a fruit filler, e.g., a fruit gel composition, containing at least one inorganic pyrophosphate.
The dog food composition, such as, dog biscuits, having a soft center portion can be prepared by any suitable method, such ~s, convention deposition of the center portion on a dough piece and then capped by another dough piece, the edges of such pieces preferably being pressed together. Such dough pieces can be formed in any suitable or conventional manner, such as, by extrusion, stamping, cutting or molding. Preferably the food composition is prepared by the coextrusion of the outer portion and the soft center portion. Any suitable dog food composition 1338l7~
shapes or dog biscuit shapes can be used, such as, bone-shaped canine biscuits. Holes can be formed in the dog food composition or dog biscuits to facilitate the escape of moisture during baking, cooking and/or drying.
The dog biscuit dough pieces can be baked using any suitable or conventional equipment and conditions. For example, the dog biscuit dough pieces can be passed into an oven such as a conventional band oven where the biscuits are baked. The conveyor belts of the oven can be coated with an edible lubricant such as a natural or synthetic cooking oil or shortening to facilitate separation from the conveyor belts of the baked products.
Temperatures in the range of about 300 to about 600F can be used. The baked dog biscuits can also be subjected to subsequent drying at temperatures of about 200 to 400F, either within the baking oven or separately, to produce the desired moisture content in the final product.
The formed dog biscuit dough pieces are baked, followed by drying, to achieve a shelf stable product without the need of any moisture barrier protection. Baking and drying temperatures and times are those conventionally used in the production of a dry canine biscuit. The pieces are dried to obta~n a biscuit having a water activity of 0.70 or less. Typically, baking temperatures and times are about 300F to about an average of 475 for about 25 minutes to about 8 minutes. Drying conditions are typically about 200 to - about 325F for about 25 minutes to about 12 minutes in a forced air dryer. On a weight basis, the moisture content of the final biscuit product is less than or equal to about 15 percent by weight and preferably about 10 to 12 percent by weight of the flnal biscult at 70 percent relative humldity.
The invention product does not lnclude any fluorine-containing compound or other fluoride lon source, or quaternary ammonium compounds. Also the invention product does not include any organic pyrophosphates.
The invention deals primarily with dogs, but has a scope of teeth-bearing non-human, mammals, such as, cats.
The invention composition can be used to reduce and control tartar accumulation on canine teeth. Based upon dog biscuits 12 the weight of commercial Milk ~one~ small inven-tion dog biscuits per day, 10 medium invention dog biscuits per day, 6 large invention dog biscuits per day or 4 extra large invention dog biscuits per day will supply about 1/4 to 1/3 of a dog's caloric requirement.
The invention also involves anlmal foods, such as, dog foods, having a coating containing at least one inorganic pyrophosphate. The above lnformation regarding inorganic pyrophosphates also applies here; the coating can contain the same amounts and type of lnorganic pyrophosphates as in the case of the soft center portion.
The coating is preferably applied to the animal food in the form of a llquefied coatlng formulatlon by any sultable means, such as, dipping, spraying, etc. The coatlng can encompass all or part of the anlmal food.
The liquefied coatlng formulatlon best contalns at least one suspension agent. The preferred suspenslon agent is a polysaccharide gum, most preferably xanthan gum. Preferably about 0.05 to 1.75 weight percent of polysaccharide gum (xanthan gum) is used. Xanthan gum is one of the few gums which acts as an acceptable suspension agent in the invention. The xanthan gum is an excellent agent for controlling the bodying effect, as it is stable over a broad temperature range, i.e., it holds the same viscosity over a large temperature range without any separation of the coating ingredients. The xanthan gum has a bodying effect so that little or no separation occurs. Other suitable gums and mucilages can be used.
Malto-dextrin produced by hydrolyzing corn starch is preferred; it serves as a carrier (bodying), binding agent and suspension agent and helps the appearance of the coating; and it is a preferred ingredient. Other malto-dextrins can also be used for the same functions.
An adhesive or binding agent,-such as, malto-dextrins, is needed in the coating slurry, to help the coating material bind (adhere) to the raw hide when the raw hide is dipped in the coating slurry. Preferably about 5 to about 15 weight percent of the malto-dextrin is included in the coating material.
A carrier, such as, starch or a modified food starch, is included in the coating formulation. Preferably about O.1 to ~about 5 weight percent of the food starch or modified food starch is included in the coating material. The food starch or modified food starch also serves to control the viscosity.
Animal fat preferably is included for flavor purposes. Other suitable flavorants can be used or included, particularly salt.
The flavorants can be any dairy product flavorant, such as milk or 1~817~

cheese, meat flavorants, such as, liver or beef, poultry and fish.
Flavorants help provide palatability for the invention coating.
Preferably a hydrogenated vegetable oil is included in the coating formulation for sheen and to modify the melting point of the formula fats in the finished product. It also helps to prevent flaking of the coating; also the coating does not have a tacky feeling.
Any suitable colorant can be included in the coating formulation. The preferred colorant is caramel color which also provides some flavor to the product.
The coating also incorporates sufficient water to achieve the liquefied coating composition. Amounts of the other ingredients are those which are effective to achieve their functions in the coating formulation.
The preferred coating formulation, besides the inorganic pyrophosphates, contain animal fat, a surfactant, such as, a modified lethicin, polysaccharide gum, a modified food starch, flavorant, colorant, hydrogenated vegetable oil, a carrier, such as a malto-dextrin, and water. A suitable humectant, preferably propylene glycol, can be used in the coating formulation.
The coating formulation should be viscous enough so that the coating formulation generally only coats the surface regions of the animal food. The presence of coating in the surface regions of the animal food helps to anchor the resultant coating and to prevent the coating from easily being separated from the animal food during handling and shipping. Basically though the coating is strictly a surface phenomena on the animal food.
The coating slurry can be applied to the animal food by any suitable means, such as, spraying, dipping, soaking in a container, etc. The coating slurry is applied generally at a temperature of 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180F. The coating slurry has a low microbial profile at such higher temperatures.
After treating the raw hide with the pyrophosphate slurry, the coated animal food is dried and/or baked. While the coated animal food is preferably air dried, it is also advantageous to dry the coated animal food using applied heat, e.g., in a hot air oven (at a temperature of say 75F to 300F).
The preferred embodiment and ranges of the above type of coating is:

Ingredients Percentages Specific Ranges Sodium acid pyrophosphate (SAPP), anhydrous powder, (non-leavening type) 1.73 0.25 to 5 Tetrapotassium pyrophosphate (TKPP), anhydrous powder 1.15 0.25 to 5 Salt 0.50 0.05 to 2.5 Malto-Dextrin 9.17 2 to 30 Modified Food Starch 2.00 0.1 to 10 Colorant 0.50 0.01 to 3 Flavorant 2.00 , 0.01 to 5 Xanthan 0.20 0.05 to 1.5 Lecithin or Modified Lecithin 1.25 0.5 to 1.75 Vegetable Fat 0.50 0.1 to 3 Animal Fat l_ 0.1 to 5 Subtotal 20.00 Water 80.00 50 to 97 Total 100.00 133817~

The following coating-baking procedure is particularly advantageous:
(a) dry blending the dry powder.
(b) adding 1/4 of the water and slurring the composition.
(c) adding remaining 3/4 of the water and mixing to form the coating formulation.
(d) heating the coating formulation to 185 to 200F with intermittent stirring (add animal fat at about 125F
during the heating).
(e) maintaining the coating formulation at 160 to 190F.
(f) apply the coating material to the unbaked dough pieces.
(g) baking the coated, unbaked dough pieces at 325F for 25 minutes.
(h) drying the baked, coated dough pieces for 25 minutes at 225F in a forced-air dryer.
The animal food within the scope of this invention needs to have a sufficient integrity to not fall apart during processing and handling, especially, so that the coating can be applied, dried/baked, etc., without losing its integrity or cracking. The animal food is best in the form of pieces or the like, such as, kibbles, biscuits, snacks, etc. The animal food pieces can be made by any suitable forming means, such as, extruding, molding, stamping, etc. The invention composition is used to reduce and control tartar accumulation on canine teeth.
The coating containing at least one inorganic pyrophosphate salt can be applied to animal foods having soft centers which may or may not contain at least one inorganic pyrophosphate. The total amount of inorganic pyrophosphate can be distributed between the coating and the soft center.
The coating can also be composed of SEALGUM* and at least one lnorganic pyrophosphate. SEALGUM* ls a tradename of Colloides Naturals Inc. of Bridgewater, New Jersey 08807 for a coating material which provides a gummed, shiny coatlng. The coatlng, for example, can be applied in the form of a sol-ution, slurry or emulslon by using a rotative coatlng machine or using spray nozzles.
The animal food can be the dog food dlsclosed ln commonly-owned U.S. Patent No. 4,904,494, filed on September 9, 1988, entltled "Chewy Dog Snacks", or commonly-owned copending Canadian Application Serlal No. 610,692, filed on September 8, 1989, of the same title. A chewy, semi-plastic, non-extruded, non-porous, microbiologically-stable dog food whlch lncludes: 12 to about 30 weight percent, based upon the total weight of the dog food, of gelatin; at least one acldulant; at least one cereal starch-contalnlng textural agent; at least one release agent; at least one taste agent;
at least one sugar; salt; and added water. The dog food ls ln a molded form. The dog food has a pH of about 3 to 5, and has a molsture content of about 10 to 25 welght percent, based upon the weight of the dog food. The process for preparlng the dog food lncludes ~a) mixing the dry components and llquld components wlth low speed agltatlon and contlnuing the mlxlng untll a dough ls obtalned; (b) formlng the dough by moldlng rotary moldlng, etc., lnto molded snacks or blscults; (c) condltloning the molded (formed) dough at 185 to 200F for *Trade mark - 97 -13~8179 about 7 to 8 minutes; and (d) packaglng the molded (formed), baked dog snacks or biscults ln a protectlve package.
The coatlng and dog blscults can be those of U.S.
Patent No. 4,822,626, and copendlng commonly-owned Canadlan Serlal No. 614,325. The blscults with a baked-on proteln-aceous coatlng, are produced comprlslng steps of (a) preparlng a dough plece from a dough comprlslng flour, meal, fat and water;
(b) enroblng the dough plece wlth a vlscous coatlng formulatlon comprlslng 10 to 30 welght percent of a dextrln carrler, 10 to 50 welght percent of meat, 10 to 30 welght percent of a glazlng agent, 1 to 5 welght percent of polysaccharlde gum, 5 to 15 welght percent of monosaccharlde sugar, 5 to 15 welght percent of a dlsaccharlde sugar, and water, all based upon total dry sollds; and (c) baklng the dough plece to form a dry blscult wlth a baked-on coatlng. The glazlng agent can comprlse a gelatln or a modlfled food starch, and the polysaccharlde gum can be a xanthan gum.
The coatlngs are modlfled by the lncluslon of at least one lnorganlc pyrophosphate.
The lnventlon also lnvolves swab, gauze and other llke materlals havlng adsorbed/adsorbed thereon a (aqueous) solutlon containlng at least one inorganic pyrophosphate. The above lnformatlon regardlng amounts, types, preferred, etc., of the lnorganlc pyrophosphates also apply here. The dlsclos-ure hereln concernlng pyrophosphate solutlons (aqueous, water/ethanol, ethanol, etc.~ ls appllcable here. The sol-utlon preferably contalns a thlckener, preferably a humectant, such as, corn syrup, sugar and polyalcohols, such as, propylene glycol (preferred), sorbltol and glycerln.
Swabs are small stlcks havlng a wad of an absorbent materlal, preferably cotton, usually wound around one end thereof. Gauze ls a loosely woven cotton (or other sultable absorbent materlal) surglcal dresslng. The gauze can have a water-proof backing.
The solution (preferably aqueous) contalnlng pyrophosphate can be applled to the swab, gauze and llke materlals by any sultable means. Preferably the sorbent or tlp portlon of the swabs contalnlng the cotton or llke materlal ls dlpped into the solutlon whlch ls usually heated at 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180F. The treated swab can be packaged ln a llquld-tlght contalner wlthout drylng. The treated swab can also be drled, preferably ln a forced-alr oven at a temperature of 75 to 300F. The gauze ls preferab-ly dlpped ln the solutlon or sprayed wlth the solutlon. The solutlons are usually and preferably heated as above. The treated gauze can be packaged ln a llquid-tlght contalner or packaged wlthout drylng. The treated gauze can also be drled as above.
The undrled or drled swabs, gauze or like material are packaged, indivldually or ln plurallty, ln llquld-tlght or alr-tlght contalners.

_ 99 _ The undrled or drled swabs, gauze or llke materlal can be used to control or reduce tartar accumulatlon on anlmal teeth, such as, dog teeth, by contactlng such teeth on a perlodlc basls - 99a -(preferably each day) with such dried, coated swabs, gauze or like material.
The invention further involves swabs, gauze and other like materials having thereon and/or therein a coating containing at least one inorganic pyrophosphate. The above information regarding amounts, types, preferred, etc., inorganic pyrophosphates also applies here. The coating can contain the same amounts and type of inorganic pyrophosphates as in the case of the soft center portion.
The coating preferably is the coating described above which contains a surfactant, such as, lecithin or modified lecithin, xanthan gum (or other suitable polysaccharide gum), a starch or modified food starch, hydrogenated vegetable oil and a carrier, such as, malto-dextrin, flavorant (optional) and colorant (optional), but not including the animal fat. The above disclosure regarding such coating also applies to this invention embodiment, as appropriate. A suitable humectant, preferably propylene glycol, can be used in the coating formulation.
The coating can be applied to the swab, gauze and like materials by any suitable means. Preferably the sorbent or tip portion of the swabs containing the cotton or like material is ~dipped into the liquefied coating composition, which is usually heated at 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180F. The coating can then be dried, preferably in a forced-air oven at a temperature of 75 to 300F.
The gauze is preferably dipped in the liquefied coating composition or sprayed with the liquefied coating composition.

The llquefled coating composltlons are usually and preferably heated as above and the drying is preferably done as above.
The dried, coated swabs, gauze or llke materlal are packaged lndlvldually or ln plurality, in alr-tlght con-tainers.
The dried, coated swabs, gauze or llke material can be used to control or reduce tartar accumulation on anlmal teeth, such as, dog teeth, by contactlng such teeth on a periodlc basls (preferably each day) wlth such drled, coated swabs, gauze or like materlal.
The lnvention involves meat ~erky, such as, beef ~erky, havlng adsorbed/adsorbed thereln and/or thereon a (drled or undrled) solutlon contalnlng a (aqueous) solutlon contalnlng at least one lnorganlc pyrophosphate. The above lnformatlon regardlng amounts, types, preferred, etc., of the lnorganlc pyrophosphates also applles here. The solution should use an aqueous, water/ethanol or ethanol solvent. As used ln thls entlre document, a solutlon can lnclude a slurry, suspension or the llke where approprlate, for example, lf a water-lnsoluble pyrophosphate ls used.
The solution can be applied to the meat ~erky by any sultable means. The meat ~erky, partlcularly beef ~erky, ls somewhat porous in structure. The solution is preferably applied by dlpplng the meat ~erky ln the solutlon, whlch ls usually at 45 to 200F, preferably at about 60 to about l90~F and most preferably at about 180F, or by spraylng the solutlon onto the meat ~erky (the solutlon temperatures belng the same as above). The treated meat ~erky can be drled by any sultable means, preferably ln a forced-alr oven at a temperature of 75 to 300F.

- lOla -1~38179 73783-60 The meat jerky can be packaged in air-tight containers.
Any meat jerky can be used. Naturally prepared jerky, also known as charqui, typically made with strips of striate muscle meat. Beef jerky products for canine consumption are usually prepared by the loaf extrusion method, the single strip extrusion method and the ribbon strip extrusion method.
Coextensively aligned jerky are described in Canadian Patent No.
1,298,139 and copending, commonly-owned Canadian Application Serial No. 560,935.
The meat jerky can be used to prevent or reduce tartar accumulation on animal teeth, such as, dog teeth, by having the animal consume the treated meat jerky on a periodical (e.g., daily) basis.
The invention involves meat jerky, such as, beef jerky, having thereon and/or therein a coating containing at least one inorganic pyrophosphate. The above information regarding the amounts, types, preferred, etc., of inorganic pyrophosphates applies here.
The coating preferably is the coating described above which contains a surfactant, such as, lecithin or modified lecithin, xanthan gum (or other suitable polysaccharide gum), a starch or modified food starch, hydrogenated vegetable oil, a carrier, such as, malto-dextrin, animal fat, flavorant, colorant and water. The above disclosure regarding such coating also applied to this invention embodiment, as appropriate. A suitable humectant, preferably propylene glycol, can be used in the coating formulation.

1338l7g The coating can be applied to the meat jerky gauze and like materials by any suitable means. Preferably the meat jerky is dipped into or sprayed with the liquefied coating composition, which is usually heated at 45 to 200F, preferably at about 60 to about 190F, and most preferably at about 180F. The coating can then be dried, preferably in a forced-air oven at a temperature of 75 to 300F.
The dried, coated meat jerky is packaged in air-tight containers.
The dried, coated, meat jerky can be used to reduce or reduce tartar accumulation on animal teeth, such as, dog teeth, by having the animal consume the treated meat jerky on a periodical (e.g., daily) basis.
The invention also includes the application of a solution containing at least one inorganic pyrophosphate onto an animal food, such as, dog biscuits, semi-moist dog food, kibbles, extruded dog snacks and food, coated dog biscuits, etc. The above information regarding amounts, types, etc., of the inorganic pyrophosphate also applies here. Preferably the edible solvent used in the solution is water.
The solution is preferably applied to the animal food by ~means of a spray device, e.g., a spray bottle or a spray can. The treated animal food is used to reduce or prevent tartar accumulation on the animal's teeth, for example, dog teeth or cat teeth, by having the animal consume such treated animal food on a periodic (e.g., daily) basis.
The following is a summary of experiments described in more detail below:

Definitions:
SAPP is sodium acid pyrophosphate (or trisodium monoacid pyrophosphate or sodium pyrophosphate).
TSPP is tetrasodium pyrophosphate.
TKPP is tetrapotassium pyrophosphate.
xample 1: Initial testing of solutions of pyrophosphates.
Solutions were applied directly to teeth.
xample 2: Addition of pyrophosphate (5 percent delivered) to Milk Bone~ formula. Milk Bon ~ is a registered trademark of Nabisco Brands, Inc. for canine biscuits.
xamPle 3: Dose response study. Pyrophosphate at 0.5, 1.5, 3.0 and 5.0 percent delivered were added to the Milk Bon ~ formula.
Examples 2 and 3 are based upon modifications of the formula of Milk Bone dog biscuits.

1338l79 Table 4 TARTAR CONTROL BISCUITS
SUMMARY OF FORMULA DEVELOPMENT

Control Ex. 2 Ex. 3 Regular 5~ Pyro- Dose Milk Bone~ Phosphate Study, Ingredients Lbs. Lbs. Lbs.
Flour 940.000 940.000 See Soybean Meal 135.000 135.000 Meat & Bone Meal100.000 100.000 Example Wheat Meal 40.000 40.000 Tallow 32.000 32.000 3 Salt 10.000 10.000 Dicalcium Phosphate8.500 8.500 Natural Flavorants17.000 17.000 Bone Meal 5.000 5.000 Calcium Carbonate 2.000 2.000 Dough Conditioners2.875 2.875 Vitamin Premix 0.375 0.375 Tetrasodium Pyrophosphate -0- 70.280 Sodium Acid Pyrophosphate -O- 23.450 Tetrapotassium Pyrophosphate -o- -~-`Calcium -0- -0-TOTAL1,292.7501,386.48 Example 1 Solution Tests Purpose To determine the dose response of three concentrations of an anti-tartar agent (pyrophosphate) to reduce accumulation of tartar formation in the dog.
Test Design Treatment DI H2O - Control 3.3% Pyrophosphate 5.0% Pyrophosphate

6.7% Pyrophosphate Test Solutions Formulas Tetrasodium Sodium Acid % Delivered Pyrophosphate (TSPP) Pyrophosphate (SAPP) Pyrophosphate 3.58 grams 1.22 grams 3.3 5.42 grams 1.85 grams 5.0

7.27 grams 2.48 grams 6.7 The above pyrophosphates were mixed with 100 ml of DI H20. The test solutions were applied to the teeth using a modified syringe. The ratio of the above blends of TSPP and SAPP is:
TSPP-75 percent, SAPP-25 percent.
pH of Test Solutions Test Solutions ~

3.3% 7.92 5.0% 7.74 6.7% 7.85 Results A significant reduction in tartar accumulation was shown with the 5 percent pyrophosphate solution.

133~179 Example 2 Pilot Plant Study With Milk Bon P
Containing 5 Percent of Deliverable Pyrophosphate Purpose The addition of pyrophosphate to Milk Bon ~ dog biscuits.
Test Tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate (SAPP) were used. The ratio of the pyrophosphates was 75 percent of TSPP and 25 percent of SAPP.
The level of TSPP was 5.1 percent and SAPP was 1.69 percent of the formula weight--which delivers approximately 5.0 percent of pyrophosphate. The TSPP and SAPP, dissolved in water, were just added to the total weight of the regular Milk Bon ~
formula. No other formula adjustments were made so that the effects of the pyrophosphates could be determined.
The study originally was designed to test Milk Bon ~ with 5.0, 7.5 and 10.0 percent of deliverable pyrophosphate. At the 7.5 and 10.0 percent levels, acceptable biscuits could not be rotary molded. The finished product was extremely soft and had distorted shapes. Biscuits with 5.0 percent of pyrophosphate were borderline acceptable. The color of the biscuits were whitish in color, whereas the control biscuits are tan/beige in color.
Results A significant reduction in the accumulation of tartar was seen at the 5 percent pyrophosphate level. There was a significant amount of breakage (30 to 35 percent) with the 5 percent pyrophosphate biscuits.

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Additional Information pH of biscuits:
Control Milk Bone~ - 6.15 5 percent of pyrophosphate Milk Bone~ - 6.98 Example 3 Pilot Plant Dose Response Study Purpose To establish a dose level which is effective for tartar control.
Test The TSPP and SAPP solutions were added to the weight of the regular Milk Bone~ formula. No other formula adjustments were made so that the effect of the pyrophosphates could be determined. The pyrophosphates were dissolved in water (135 to 140F) and added to the Milk Bon ~ dries. Regular medium Milk Bone~ and four medium Milk Bone~ test products were made.
Each of the test products contained different levels, 0.5, 1.5, 3.0 and 5.0 percent of deliverable pyrophosphates. The ratio of the blend of tetrasodium pyrophosphate (TSPP) and sodium acid pyrophosphate (SAPP) was:

TSPP - 75%}
~ for all four levels SAPP - 25~}
The total amounts of TSPP and SAPP added to the formula and approximate delivered soluble pyrophosphate (P2O7) were:

133817!~

% % % %
(75%) TSPP added -0.54 1.603.17 5.10 (25%) SAPP added -0.18 0.531.10 1.69 Total 0.72 2.134.27 6.79 Approx. delivery of soluble pyro-phosphate - 0.5% 1.5%3.0% 5.0%
Pilot Plant Trials The doughs containing 0.5 and 1.5 percent of delivered pyrophosphates were similar in development to control regular Milk Bon ~ dog biscuits. However, the doughs with the 3 and 5 percent levels were shorter in texture and not as developed as the control. The finished products at these two levels were less hard than the control biscuits.
~H - of Biscuits (10% solution) Regular Milk Bon ~ - 6.10 0.5% biscuits - 6.41 1.5% biscuits - 6.75 3.0% biscuits - 6.88 5.0% biscuits - 7.07 Results of the Study Pyrophosphate Delivery Results 0.5% Milk Bon ~ biscuits No significant reduction in tartar accumulation -directional trend 1.5% Milk Bon ~ biscuits No significant reduction in tartar accumulation -directional trend 3.0% Milk Bone~ biscuits A significant reduction in tartar accumulation .0% Milk Bon ~ biscuits A significant reduction in tartar accumulation A significant amount of breakage (approx. 25 percent) was reported for the 5 percent pyrophosphate biscuits. There was approximately 15 percent breakage with the 3 percent level.
At the 0.5 and 1.5 percent of pyrophosphate levels, the breakage was not considered excessive compared to the control biscuits.
Test data and results are set out in the following table:

REGULAR MILK BONER/PTKOR; - IIATE/TARTAR CONTROL
DOSE RESPONSE STUDY

PYRO- PYRO-CONTINUOUS PHOSPHATE PHOSPHATE
MIX CONTROL .50X 1.50%
INGREDIENTS LBS PERCENT LBS. PERCENTLbs. PERCENT
Flour 940.00 72.7132 940.00 72.1855940.00 71.1604 Soy Heal 135.00 10.4429 135.0010.3671 135.00 10.2198 Meat ~ Bone Meal 100.00 7.n54 100.00 7.6793100.00 7.5703 ~heat Meal 40.00 3.0942 40.00 3.071740.00 3.0281 Tallo~ 32.00 2.4753 32.00 2.457432.00 2.4225 Salt 10.00 o. m 5 10.00 0.767910.00 0.7570 Dicalcium Phosphate 8.50 0.6575 8.50 0.65278.50 0.6435 Natural Flavorants 17.00 1.3157 17.00 1.305617.00 1.2869 Bone Meal 5.00 0.3868 5.00 0.38405.00 0.3785 Calcium Carbonate 2.00 0.1547 2.00 0.15362.00 0.1514 Dough Conditioners 2.875 0.2224 2.875 0.22082.875 0.2176 Vitamin Premix 0.375 0.0290 0.375 0.02880.375 0.0284 Tetrasodium Py.u~,uD~hate -0- -0- 7.07 0.5429 21.14 1.6003 Sodium Acid Py,u~h~a~.ate -0- -0- 2.38 0.1828 7.07 0.5352 TOTAL 1,292.75 1,302.2 1,320.96 TABLE 5 (CONT.) PrRO- PrRO-PHOSPHATE PHOSPHATE
3.0% 5.0%
INGREDIENTS LBS. PERCENT BS. PERCENT
Flour 940.00 69.6797 940.00 67.7976 Soy Meal 135.00 10.0072 135.00 9.7369 Meat & Bone Meal 100.00 7.4127 100.00 7.2125 ~heat Meal 40.00 2.9651 40.00 2.8850 Tallo~ 32.00 2.3721 32.00 2.3080 Salt 10.00 0.7413 10.00 0.7213 Dicalcium Phosphate 8.50 0.6301 8.50 0.6131 Natural Flavorants 17.00 1.2601 17.00 1.2261 Bone Meal 5.00 0.3706 5.00 0.3606 Calcium Carbonate 2.00 0.1483 2.00 0.1443 Dough Conditioners 2.875 0.2132 2.875 0.2074 Vitamin Premix 0.375 0.0278 0.375 0.0270 Tetrasodium Py,u~ho~,ate 42.210 3.1289 70.28 5.0689 Sodium Acid Py~u~,o~,ate 14.070 1.0430 23.45 1.6913 TOTAL 1,349.03 1,386.48 The following is a summary of experiments described in more detail below:
xample 4: Initial testing of solutions of pyrophosphates.
Solutions were applied directly to teeth. Same as Example 1.
xample 5: Addition of pyrophosphate (5 percent delivered) to Milk Bon ~ formula. Same as Example 2.
xample 6: Dose response study. Pyrophosphate at 0.5, 1.5, 3.0 and 5.0 percent delivered were added to the Milk Bon ~ formula. Same as Example 3.
xamPle 7: Base line formula. Used to determine the effects of pyrophosphate on the nutritional aspects of Milk Bon ~ formula.
xample 8: 2.57 percent pyrophosphate delivery. This formula was modified to balance calcium and phosphorus ratio (eliminated dicalcium phosphate and bone meal, and increased calcium carbonate).
xample 9: 2.34 percent pyrophosphate delivery. This formula was modified to balance sodium and chloride (substituted TKPP for TSPP, eliminated salt, added CaCl2 and reduced CaC03).
xample 10: Same as Example 9, but with increased tallow (and increased water).
xample 11: Lower pyrophosphate delivery (1.6 percent pyrophosphate) than Example 10.
Examples 4 to 11 are based upon modifications of the ormula of Milk Bon ~ dog biscuits.

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TARTAR CONTROL BISCUITS
SUMMARr OF FORMULA DEVELOPMENT

EX. 8 EX. 9 EX. 10 CONTROL EX. 5 EX. 6 EX. 7 FORMULA FORMULAFORMULA
REGULAR 5% PYRO- DOSE BASELINE#3 2.5Z 4A 2.3%4B 2.34%
MILK BONEPHOSP~ATESTUDYFORMULA PYRO. PYRO. PYRO.
INGREDIENTS LBS. LBS. LBS. LBS. LBS. LBS. LBS.
Flour 940.000940.000 See 940.000 940.000940.000 940.000 Soybean Meal 135.000 135.000 135.000135.000 135.000135.000 Meat & Bone Meal 100.000 100.000Example100.000100.000 100.000100.000 wheat Meal 40.000 40.000 40.000 40.000 40.000 40.000 Tallow 32.000 32.000 No. 3 32.000 32.000 32.000 37.000 Salt 10.000 10.000 10.000 Dicalcium Phosphate8.500 8.500 8.500 -0- -0- -0-Natural Flavorants17.000 17.000 17.000 17.000 17.000 17.000 Bone Meal 5.000 5.000 5.000 -0- -0- -0-Calcium Carbonate 2.000 2.000 2.000 37.000 25.000 25.000 Dough Conditioners2.875 2.875 2.875 2.875 2.875 2.875 Vitamin Premix 0.375 0.375 0.375 0.375 0.375 0.375 Tetrasodium PyIo~,os~,ate -0- 70.280 18.800 19.000 -0- -0-Sodium Acid Pyro~,os~,ate -0- 23.450 28.200 28.500 27.000 27.000 Tetrapotassium Py,u~,os~,ate -0- -0- -0- -0- 18.000 18.000 Calcium Chloride -0- -0- -0- -0- 13.500 13.500 TOTAL 1,292.7501,386.48 1,339.7501,375.2501,350.750 1,355.25 Note: 1. Example 10 rapr~s_,ts a preferred formula having 2.34 ~eight percent of ~t,u~ho~,ate.

11~

Example 7 - TSPP AND SAPP added at appropriate ratio and levels - No other formula changes were made Purpose The formula serves as a base line formula to determine the effects of TSPP and SAPP on the nutritional aspects of the formula. The nutritional data was generated by a computer program. It was determined that the FDA generally recognized as safe (GRAS) status for sodium acid pyrophosphate in baked goods is a maximum level of 2.1 percent and 1.4 percent for tetrasodium pyrophosphate, therefore, the levels and ratios of TSPP and SAPP had to be changed.
Chanqes:
The original ratio of TSPP (75 percent) and SAPP (25 percent) was changed to:
SAPP - 60%
TSPP - 40%
To achieve maximum delivery of pyrophosphates the maximum GRAS
allowed levels are used. At these levels the above ratios are required. TSPP and SAPP were incorporated into the regular ~ilk Bone~ formula - no other changes were made.
Using the allowed maximum levels (TSPP 1.4 percent and SAPP 2.1 percent) and the new ratios of 60 percent SAPP and 40 percent TSPP the following nutritional data was generated on a computer program.

Results 1338179 Nutritional data:
Calcium -l.lS9%} 1.0 } to Phosphorus -1.888%} 1.629 Ratio Potassium -0.813%
Sodium -1.352%
Chloride -0.504%
The calcium and phosphorus ratio per the National Research Council (NRC) requirements is 1.1:1.4 to 1. In this base line formula the ratio is reversed, i.e., phosphorus 1.629 to calcium 1Ø The sodium was high.
Total amount of TSPP and SAPP added = 3.5%
Soluble pyrophosphate delivery = 2.5%
Example 8 2.57% Soluble Pyrophosphate Delivery Pilot Plant Study Purpose To modify formula to balance calcium and phosphorus ratio. To evaluate the effect of adding TSPP and SAPP in dry form to the Milk Bone~ formula. In the prior examples the ~yrophosphates were dissolved in water.
Test To balance calcium and phosphorus ratio, the following formula changes were made:
- Eliminated dicalcium phosphate - this decreased the calcium and phosphorus level.

13~8179 - Eliminated bone meal - this decreased the calcium and phosphorus.
Purpose of above changes was primarily to decrease the phosphorus content.
However, to compensate for the decreases in calcium from the above change, the following formula change was made:
- Increased calcium carbonate to increase calcium level.
- Dicalcium phosphate, bone meal and calcium carbonate are ingredients in regular Milk Bon ~.
- Evaluate the effect of formula changes (omission of the dicalcium phosphate and bone meal and increase calcium carbonate) on mixing rotary molding.
Results: Formula #5 Nutritional Data Calcium 1.807}
) 1.1 to 1.0 ratio Phosphorus 1.690 Potassium 0.799 Sodium 1.336 Chloride 0.495 Results The formula of Example 8 has an acceptable calcium to phosphorus ratio. (It is best not to go over 1.9 percent of calcium). The lowering of the sodium level and the raising of the chloride level, but not over the 0.8 percent level, are recommended. The above nutritional data represents only the nutrients most affected by the addition of TSPP and SAPP.

1~38179 Pilot Plant Trials (Formula of Example 8) Purpose To evaluate the effect on dough development of adding TSPP and SAPP in dry form (blended with Milk Bon ~ dries).
Granular TSPP and SAPP were used for the trials. To evaluate the affect of the adjustments made by the omission of dicalcium phosphate and bone meal and the increase of calcium carbonate. All of the changes influence the water absorption properties of the formula. The TSPP and SAPP may also influence the protein (gluten) development.
Results The granular TSPP and SAPP did not dissolve and could be seen throughout the dough and finished product. The doughs were not fully developed (crumbly) and short. With the addition of extra water the doughs were becoming sticky - this would create problems with the rotary molding of biscuits.
pH of biscuits: Control 1, 6.12; Example 6(3) formula, 6.36.
This example disclosed: The tetrasodium pyrophosphate (TSPP) should be with tetrapotassium pyrophosphate (TKPP).
This change will decrease sodium level - but increase potassium. The salt should be eliminated from the formula.
This change will decrease the sodium and chloride levels.
Calcium chloride should be added. This will increase the chloride to an acceptable level. However, this change will also increase the calcium. Therefore, calcium carbonate will be decreased to keep the calcium and phosphorus ratio in balance. It is best not to go over 1 percent of calcium 133817~
chloride in the formula. There should be a change from granular to powdered pyrophosphates.
Example 9 2.34% Soluble Pyrophosphate Delivery Pilot Plant Study Purpose To balance the sodium and chloride levels. To produce a product for palatability kennel testing.
Formula changes:
Changes in the formula were:
Eliminated salt from formula - decreases sodium and-chloride.
Replaced TSPP with TKPP - decreases sodium - increases potassium.
Added calcium chloride - to increase chloride.
Decreased calcium carbonate due to addition of calcium chloride which increased calcium level.
Changed to powdered pyrophosphates instead of granular pyrophosphates.
Results Nutritional data Calcium % 1.843~ 1.16 ) to ratio Phosphorus % 1.585) 1.0 Potassium % 1.252 Sodium % 0.516 Chloride % 0.662 The formula was found to be acceptable (nutritionally balanced). This includes potassium, sodium and chloride.
Tetrapotassium pyrophosphate delivers less pyrophosphate than (TSPP) tetrasodium pyrophosphate. This is the reason for the reduction of soluble pyrophosphate delivery.
Pilot Plant Trials Purpose To evaluate the use of powdered TKPP and SAPP. To evaluate the effect on dough and finished product due to ingredient changes in formula.
Results The powdered TKPP and SAPP were not visible (by eye) throughout the dough and finished product. The development of the dough was approximately the same as in the formula of Example 8. It was short and on the crumbly side and approaching stickiness. It was felt that the addition of more water would increase stickiness and result in poor machining of biscuits.
pH of Biscuits; control 6.0; formula of Example 9, 5.75 This example disclosed the following changes should be made: The addition of more tallow. Standard Milk Bon ~
formula contains 32 pounds of tallow - will increase to 37 pounds. With the addition of extra tallow, extra water will be added to the formula to help minimize dough stickiness.
The extra tallow should also improve palatability.
Palatability Kennel Test Results - Formula of Example 9.
Kennel Test Control (regular Milk Bone~ formula) vs. Formula of Example 9 (standard water and standard tallow level).
Results - No significant preference was shown between the two products.
Example 10 2.34% Soluble Pyrophosphate Delivery Pilot Plant Study Purpose To evaluate the mixing, machining and finished product of the Formula of Example 9 with a slight increase in tallow.
With the addition of extra tallow, the water will be increased for better dough development.
Formula Changes Increased tallow from 32 pounds to 37 pounds.
Results Nutritional Data - Formula of Example 10 See below.
pH of biscuits: control, 6.1; Formula of Example 10, 5.8.
Pilot Plant Trials Purpose Same as above.
Three batches were made: (1) control standard Milk Bone~
formula; (2) pyrophosphate biscuits (Test #l) with previous water level; (3) pyrophosphate biscuits (Test #2) with increased water. Test #1 and Test #2 - have the same increased level of tallow. Sufficient quantities of the three batches were made for palatability kennel testing.

13~8179 Results Test #l - used previous water level but lncreased the tallow. The dough was improved over previous doughs. How-ever, it stlll was short and crumbly. The finished product had a rough surface--there was no stickiness.
Test #2 - used increased water and tallow which resulted in a smoother more developed dough. The flnlshed product was also smoother with less surface cracks. The hardness values of the blscults are close to control Mllk Bone~ hardness.
The tallow and water ad~ustments were made ln the pilot plant uslng a horlzontal mlxer. The above processlng lmprovements were evaluated ln actual plant trlals uslng a continuous mixer with improved processing results.
Kennel Test Results Kennel Test Control vs. Test #l - a slgnificant preference was shown for Test #l product.
Kennel Test:
0 Control vs. Test #2 - a significant preference was shown for Test #2 product.
This Example ls a preferred composltlon, and Test #2 ls a preferred processlng embodlment.
Nutrltlonal Data - Formula of Example 10 Calclum - 1.843%
Phosphorus - 1.585%
Potasslum - 1.252%
Sodium - 0.516%

13~8179 Chloride -0.662%
Example 11 1.6% Pyrophosphate Delivery Pilot Plant Study Purpose To develop a Milk Bon ~ formula containing a lower level of pyrophosphate (SAPP and TKPP). The level is approximately 1.6 percent of delivered pyrophosphate. With the lower levels of SAPP and TKPP, less formula adjustments are needed to meet nutritional requirements of the National Research Council (NRC).
Formula Changes (Example lla) The changes in this formula are compared to the formula of Example 10:
Calcium Carbonate - decreased from 37 to 15 lbs.
Calcium Chloride - decreased from 13.5 to 13 lbs.
TKPP - decreased from 18 to 12 lbs.
SAPP - decreased from 27 to 18 lbs.
Sodium Bicarbonate - Added as a leavening agent Results - Nutritional data Calcium -1.581%}
~ 1.2 to 1.0 ratio Phosphorus -1.333%) Potassium -1.105%
Sodium -0.488%
Chloride -0.651%
The Example lla formula is the most preferred composition.

Formula - Example llb This formula is basically the same as the formula of lla.
The only differences are: The meat and bone meal was decreased from 100 to 90 pounds. The level of the one component of the natural flavorants (i.e., fish meal) was increased by 10 pounds.
Results - Nutritional data Calcium - 1.551%}
} 1.2 to 1.0 ratio Phosphorus - 1.322%}
Potassium -- 1.099%
Sodium - 0.485%
Chloride - 0.651%
pH of biscuits Regular Milk Bon ~ - 6.18 Formula Ex. lla - 5.88 Formula Ex. llb - 5.93 Additional Information Regarding the formulas of Examples lla and llb:
The ratio of the blend of TKPP and SAPP is:
60% of SAPP and 40% of TKPP
The level of each pyrophosphate is:
SAPP - 1.35% of formula total weight TKPP - 0.899% of formula total weight Test data and results are set out in the following table:

3~3~

Example 11a TARTAR COUTROL BISCUITS
PrRu,n NATE - APPROXIMATE DELIVERY 1.6%

INGREDIENTS Lbs. PERCENT
Flour 940.000 70.400 Soy Bean Meal 135.000 10.110 Meat and Bone Meal 100.000 7.489 ~heat Feed 40.000 2.996 Tallow 37.000 2.771 Sodium Acid Py,u~,os~,ate Anhydrous 18.000 1.348 tPwd.) Calcium Carbonate 15.000 1.123 Calcium Chloride ~Pwd.~ Anhydrous13.000 0.974 Tetrapotassium Py,u~,o~,ate Anhydrous (Pwd.) 12.000 0.899 Natural Flavorants 17.00 1.272 Sodium B'icarbonate 5.000 0.374 Dough Conditioners 2.875 0.216 Vitamin Premix 0.375 0.028 TOTAL 1,335.250 100.000 /~,S

1338:179 TABLE 7 (CONT.) Example 11b PrKOF;~ ATE - APPROXIMATE DELIVER~ 1.6X

INGREDIENTS LBS PERCENT
Flour 940.000 70.400 Soy Bean Meal 135.000 10.110 Meat and Bone Meal 90.000 6.740 ~heat Feed 40.000 2.996 Tallo~ 37.000 2.771 Sodium Acid Py~o~,os~,ate Anhydrous 18.000 1.348 ~Pwd.) Calcium Carbonate 15.000 1.123 Calcium Chloride (P~d.) Anhydrous 13.000 0.974 Tetrapotassium Pyro~,os~,ate Anhydrous (Pwd.) 12.000 0.899 Natural Flavorants 5.000 0.374 Sodium Bicarbonate 27.000 2.021 Dough Conditioner 2.875 0.216 Vitamin Premix 0.375 0.028 TOTAL 1,335.250 100.000 In Examples 12 to 28 the following procedure was used:
The coated raw hide strips were prepared by:
(a) blending the dry powders.
(b) adding 1/4 of the water and slurring the composition.
(c) adding remaining 3/4 of water and mixing to form the coating formulation.
(d) heating the coating formulation to 185F to 200F.
with intermittent stirring (add animal fat at about 125F during the heating).
(e) maintaining the coating formulation at 160" to l90"F, (f) immersing raw hide strips by dipping in the heated coating formulation and holding the raw hide strips to the edge to let drain for aobut 15 seconds.
(g) placing the coated raw hide strips on a screen and drying at 275F for 7 minutes in a forced-air laboratory oven.
(h) let the raw hide strips cool and then package them.
Any deviations from such procedure is set out in the specific examples.
The raw hide strips had a calculated average weight of 17 grams each, although actual weight ranged from 8.5 to 335 grams.
The specific ingredients, conditions, etc., are set out in the following tables:

13~8179 Table 9 Ingredients, Examples Percentages bY weiqht 12 13 14 15 SAPP
TSPP 2.3 2.3 2.3 Malto-dextrin A 10.0 10.0 5.0 Malto-dextrin B 5.0 Food starch modified 5.0 Colorant 0.5 0.5 0.5 0.5 Flavorant 1.0 1.0 1.0 1.0 Xanthan gum 1.0 1.0 1.0 1.0 Gelatin 6.0 Water 87.5 81.8 81.8 81.8 Heated coating to 180Fyes yes yes yes pH of mixture at 160F 6.4 5.97 5.87 5.8 Raw hide dry only weight 13.811 24.962 14.705 11.289 24.655 23.957 9.485 17.936 Raw hide wet weight 28.650 21.480 13.399 33.840 27.280 20.420 Dried at 200F for: 15 min. 10 min. 15 min. 10 min.
Raw hide dry weight 25.977 16.738 11.782 27.348 24.825 18.546 Notes 1. The pH of the water was 8Ø
Comments - In Example 12, the coatlng was thick, had a nlce appearance and had a weight plck up of 2.7 g.
- In Example 13, the coatlng was very thln, had a blotchy appearance and dld not adhere evenly on the raw hide.
- In Example 14, the coatlng was thick and had a nice appearance.
- In Example 15, the coating was thin and had a blotchy appearance.

Table 10 Ingredients, Examples Parts by weight 16 17 18 SAPP 3.2 3.2 3.2 TSPP 2.13 2.13 2.13 Malto-dextrin B 10 10 10 Modified Food Starch 2.0 2.0 2.0 Cereal 0.5 0.5 0.5 Flavorant 1.0 1.0 1.0 Xanthan gum 0.2 0.2 0.2 Modified lecithin 1.0 Animal fat 2.0 Water 81.0 80.0 79.0 pH at 160F (coating) 5.9 5.9 5.9 Raw hide dry only weight 18.171 18.843 18.017 14.346 23.897 16.046 Raw hide wet weight 20.340 21.300 20.070 16.730 26.660. 18.020 Dried at 200-225F 15 min. 15 min. 15 min Raw hide (finished)dry weight 18.613 19.432 18.323 14.553 24.484 16.265 1~38179 Notes: 1. The pH of the water was 8.3.
Comments:
- In Example 10, the coating had a blotchy appearance.
- In Example 17, the coating was considered best of Examples 16 to 18, had an even distribution appearance and was complete.
- In Example 18, the coating again had a blotchy appearance.

1~3~179 Table 11 Ingredients, Examples Parts by weight 19 20 21 22 23 SAPP 1.73 1.73 1.73 1.73 1.73 TSPP 1.15 1.15 1.15 1.15 1.15 Malto-dextrin B 11.00 11.00 12.0 11.0 9.67 Modified Food Starch 2.0 2.0 1.5 2.0 Cereal 0.5 0.5 0.5 0.5 0.5 Flavorant 2.42 2.42 2.42 2.42 2.0 Xanthan gum 0.2 0.2 0.2 0.2 0.2 Modified lecithin 1.0 1.0 1.0 1.0 1.0 Animal fat 1.0 Water 80.0 79 80 80 80 Heated coating form. yes yes yes yes yes to 180F
pH at 160F (coating) 5.9 5.9 6.0 6.0 6.0 Raw hide dry only weight 18.082 16.928 12.983 12.211 15.91715.247 15.037 15.077 15.304 12.073 Raw hide wet weight 21.189 14.690 15.930 15.130 19.160 18.575 18.310 18.000 18.370 14.178 Dried at 225F 15 min. 15 min. 15 min. 15 min. 15 min Raw hide (finished) 18.846 12,472 13.,621 12.776 16.590 dry weight 15.987 15.688 15.588 15.947 12.586 Notes: 1. The pH of the water was 8.2.
2. Drying at 350 and 325F for 5 minutes curled the raw hide. It was satisfactory to dry at 300F for 7 minutes.
Comments:
- In Example 19, the coating had a good appearance.
- In Example 20, the coating was better than that of Example 21 and similar to that of Example 19.
- In Example 21, the coating was satisfactory.
- In Example 22, the coating was similar to those of Examples 19 and 20 and was better than that of Example 21.
- Example 23, best of all results.

133817~

Table 12 Ingredients ExamPles parts by weight 24 25 26 27 28 SAPP 1.73 1.73 1.73 1.73 TSPP 1.15 1.15 1.15 1.15 Malto-dextrin B 0.5 0.5 0.5 0.5 0.5 Modified Food Starch 9.17 9.5 10.05 8.73 8.81 Colorant 0.5 0.5 0.5 0.5 Flavorant 2.0 2.17 2.0 2.0 2.0 Xanthan gum 0.2 0.2 0.2 0.2 0.2 Modified lecithgran 1.25 1.25 1.25 1.25 1.25 Vegetable fat 0.5 0.5 0.5 0.5 0.5 Animal fat 1.0 1.0 1.0 1.0 1.0 Water 80 80 82.0 79.0 80.0 Heated coating to 180F yes yes yes yes yes pH at 160F (coating) 5.8-6 5.8 5.7 7.5 Raw hide dry only weight 20.867 32.990 19.134 16.634 12.680 23.233 24.136 13.786 111.883 11.987 Raw hide wet weight 24.140 36.610 22.150 19.040 26.290 27.580 15.900 14.140 Dried at 200-225F 7 min. 7 min. 7 min. 7 min. 7 min.
Raw hide (finished) 21.720 34.056 19.803 17.025 dry weight 23.907 25.015 13~8179 otes: 1. The pH of the water was 8.
2. The treated raw hide strips had an average weight of 20.18 g, the untreated raw hide strips had an average weight of 18.92g, and the average weight pickup was 1.25 g.
Comments:
- In Example 24, the coating was a good one.
- In Example 25, the coating was a good one but had no color in the formula.
- In Example 26, the coating was a good one.
- In Example 27, the coating formulation had good dispersion but there was excessive foaming.
- In Example 28, there was less foaming but did not aid dispersion.

Claims (53)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Baked dog food comprising a soft center portion and an outer portion, the center portion comprising at least one alkali metal inorganic pyrophosphate, the center portion being softer than the outer portion, the center portion containing about 0.1 to about 10 weight percent of said at least one alkali metal inorganic pyrophosphate, based upon the total weight of the baked dog food, said at least one alkali metal inorganic pyrophosphate being water soluble, the baked dog food being slightly acidic to neutral, the baked dog food having a water activity of 0.70 or less, and the baked dog food containing 15 weight percent or less, based upon the total weight of the baked dog food, of water.

2. The baked dog food as claimed in claim 1 wherein said at least one alkali metal inorganic pyrophosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate, the soft center portion is composed of a soft dog biscuit dough and said at least one alkali metal inorganic pyrophosphate, and the soft dog biscuit dough contains a humectant.

3. The baked dog food as claimed in claim 1 wherein said at least one alkali metal inorganic pyrophosphate is a combination of sodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

4. Meat jerky comprising meat jerky containing at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.1 to about 5 weight percent, based on the total weight of the meat jerky containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal inorganic pyrophosphate being water soluble, and said meat jerky being slightly acidic to neutral.

5. The meat jerky as claimed in claim 4 wherein said at least one alkali metal inorganic pyrophosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

6. Process for making a baked biscuit for the prevention of tartar accumulation on the teeth of a dog or a cat, by chewing or eating by the dog or cat of a tartar inhibiting amount of at least one baked dog biscuit or baked cat biscuit, respectively, the process comprising forming a dough by admixing ingredients comprising flour, water, and an effective antitartar amount of at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.5 to about 3.5 weight percent, based on the total weight of the at least one baked dog biscuit or baked cat biscuit containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal pyrophosphate being water soluble, forming the dough into pieces, and baking the pieces, the at least one baked dog biscuit or baked cat biscuit containing at least one alkali metal inorganic pyrophosphate being slightly acid to near neutral, the at least one baked dog biscuit or baked cat biscuit having a water activity of 0.70 or less, and the at least one baked dog biscuit or baked cat biscuit containing about 5 to about 15 weight percent, based on the total weight of the at least one baked dog biscuit or baked cat biscuit, of water.

7. The process as claimed in claim 6 wherein the alkali metal inorganic pyrophosphate is tetrasodium pyrophosphate and the dough is formed into pieces by rotary molding.

8. The process as claimed in claim 6 wherein the at least one inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

9. Baked nutritionally-balanced dog biscuit comprising about 0.1 to about 10 weight percent of at least one alkali metal inorganic pyrophosphate, about 0.1 to about 7 weight percent of Ca, about 0.08 to about 6 weight percent of P, about 0.05 to about 3 weight percent of K, about 0.1 to about 3 weight percent of Na and about 0.15 to about 4.5 weight percent of Cl-, all of said weight percents being based upon the total weight of the dog biscuit, the weight ratio of Ca to P being between about 1.0:1 and about 1.6:1, the baked dog biscuit having a moisture content of about 5 to about 13 weight percent, based upon the total weight of the dog biscuit, said at least one alkali metal pyrophosphate being water soluble, the dog biscuit being slightly acid to neutral, and the dog biscuit having a water activity of 0.70 or less.

10. The dog biscuit as claimed in claim 9 wherein the alkali metal inorganic pyrophosphate is tetrasodium pyrophosphate.

11. The dog biscuit as claimed in claim 9 wherein the at least one inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

12. The dog biscuit as claimed in claim 9 wherein the dog biscuit contains about 0.5 to about 4 weight percent of Ca, about 0.4 to about 3 weight percent of P, about 0.15 to about 3 weight percent of K, about 0.2 to about 2 weight percent of Na, about 0.3 to about 3 weight percent of Cl-, and about 0.5 to about 5 weight percent of said at least one alkali metal inorganic pyrophosphate compound, all of said weight percents being based upon the total weight of the dog biscuit, the weight ratio of Ca to P being between about 1.1:1 and about 1.4:1.

13. The dog biscuit as claimed in claim 9 wherein the dog biscuit is bone shaped.

14. Process for making raw hide for the prevention of tartar accumulation on the teeth of a dog, by chewing or eating by the dog of a tartar inhibiting amount of raw hide, the process comprising coating raw hide with an edible coating comprising an effective antitartar amount of at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.1 to about 5 weight percent, based on the total weight of the raw hide containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal inorganic pyrophosphate being water soluble, and drying the coating, the raw hide containing an edible coating containing at least one alkali metal inorganic pyrophosphate being slightly acid to near neutral, and the raw hide containing an edible coating containing at least one alkali metal inorganic pyrophosphate being chewable, tough and flexible.

15. The process as claimed in claim 14 wherein the amount of said at least one alkali metal inorganic pyrophosphate is sufficient to deliver from 0.1 to 0.5 weight percent, based on the total weight of the raw hide containing at least one alkali metal inorganic pyrophosphate, of P2O7.

16. The process as claimed in claim 14 wherein said at least one alkali metal inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate, and the weight ratio of trisodium monoacid pyrophosphate to tetrapotassium pyrophosphate is between 0.01 to 99.99 and 99.99 to 0.01.

17. The process as claimed in claim 14 wherein the coating contains at least one surfactant or emulsifier which is lecithin or a modified lecithin surfactant, at least one suspension agent which is xanthan gum, a binding or adhesive agent which is a malto-dextrin, and a carrier which is a food starch or a modified food starch.

18. The process as claimed in claim 14 wherein the raw hide is in strip form.

19. Baked dog biscuit having an edible coating containing at least one alkali metal inorganic pyrophosphate, the coating containing about 0.1 to about 10 weight percent of said at least one alkali metal inorganic pyrophosphate, based upon the total weight of the baked dog biscuit, said at least one alkali metal inorganic pyrophosphate being water soluble, the baked dog biscuit being slightly acidic to neutral, the baked dog biscuit having a water activity of 0.70 or less, and the baked dog biscuit containing 5 to 13 weight percent or less, based upon the total weight of the baked dog biscuit, of water.

20. The baked dog biscuit as claimed in claim 19 wherein said at least one alkali metal inorganic pyrophosphate is a combination of sodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

21. The baked dog biscuit as claimed in claim 19 wherein the coating contains about 0.25 to about 5 weight percent of said at least one alkali metal inorganic pyrophosphate.

22. The baked dog biscuit as claimed in claim 19 wherein the baked dog biscuit is bone shaped, and the baked dog biscuit does not contain any organic pyrophosphate, any fluorine-containing compound, any fluoride ion source or any quaternary ammonium compound.

23. The baked dog biscuit as claimed in claim 19 wherein the coating contains at least one surfactant or emulsifier, which is lecithin or a modified lecithin surfactant, a suspension agent, which is xanthan gum, a binding agent which is a maltodextrin, and a carrier, which is a food starch or a modified food starch.

24. Process for making pet foods for the prevention of tartar accumulation on the teeth of a dentulous animal, by chewing or eating by the animal of a tartar inhibiting amount of animal food, the process comprising coating an animal food with an effective antitartar amount of at least one alkali metal inorganic pyrophosphate, the amount of said at least one alkali metal inorganic pyrophosphate being sufficient to deliver from about 0.1 to about 5 weight percent, based on the total weight of the animal food containing at least one alkali metal inorganic pyrophosphate, of P2O7, said at least one alkali metal inorganic pyrophosphate being water soluble.

25. The process as claimed in claim 24 wherein the amount of said at least one alkali metal inorganic pyrophosphate is sufficient to deliver from 0.4 to 0.5 weight percent, based on the total weight of the animal food containing at least one alkali metal inorganic pyrophosphate of P2O7.

26. The process as claimed in claim 24 wherein said at least one alkali metal inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate, and the weight ratio of trisodium monoacid pyrophosphate to tetrapotassium pyrophosphate is between 0.01 to 99.99 and 99.99 to 0.01.

27. The process as claimed in claim 24 wherein said at least one alkali metal inorganic phosphate is selected from the group consisting of tetrasodium pyrophosphate, trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

28. The process as claimed in claim 24 wherein the animal food is raw hide in strip form.

29. A baked dog or cat biscuit which comprises a tartar-reduction effective amount of at least one metal inorganic phosphate of the formula Mn+2PnO3n+1, wherein M is a univalent metal and n is 2, 3, 4 or 5, or of the formula M'nPnO3n+1, where M' is a divalent metal and n has the above meaning, said at least one metal phosphate having an oxide ratio of cationic oxides (M2O
or M'O) and anionic oxides (P2O5) being between 1 and 2 or being 2.

30. A baked dog or cat biscuit as claimed in claim 29 wherein the baked dog or cat biscuit contains about 0.1 to about 10 weight percent of said at least one metal inorganic phosphate.

31. A baked dog or cat biscuit as claimed in claim 30 wherein the baked dog or cat biscuit has a moisture content of about 5 to about 15 weight percent.

32. A baked dog or cat biscuit as claimed in claim 29 wherein the baked dog or cat biscuit contains about 0.5 to about 5 weight percent of said at least one metal inorganic phosphate.

33. A baked dog or cat biscuit as claimed in claim 30 wherein the at least one metal inorganic phosphate is an alkali metal pyrophosphate.

34. A baked dog or cat biscuit as claimed in claim 30 wherein the at least one alkali metal inorganic pyrophosphate is tetrasodium pyrophosphate.

35. A baked dog or cat biscuit as claimed in claim 30 wherein the at least one metal inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate or tetrasodium pyrophosphate.

36. A baked dog or cat biscuit as claimed in claim 30 wherein the at least one metal inorganic phosphate has the formula Mn+2PnO3n+1, and the oxide ratio of cationic oxides and anionic oxides is between 1 and 2.

37. A baked dog or cat biscuit as claimed in claim 29 wherein the baked dog biscuit is bone shaped.

38. A baked dog or cat biscuit as claimed in claim 29 wherein the at least one metal inorganic phosphate has the formula Mn+2PnO3n+1, and the oxide ratio of cationic oxides and anionic oxides is between 1 and 2.

39. A baked dog or cat biscuit as claimed in claim 38 wherein n is 3.

40. A baked dog or cat biscuit as claimed in claim 30 wherein the at least one metal inorganic phosphate is an alkaline earth pyrophosphate.

41. A baked dog or cat biscuit comprising about 0.1 to about 10 weight percent of at least one alkali metal inorganic pyrophosphate, the baked dog or cat biscuit having a moisture content of about 5 to about 15 weight percent, based upon the total weight of the baked dog or cat biscuit, said at least one alkali metal inorganic pyrophosphate being water soluble, the baked dog or cat biscuit being slightly acid to neutral, and the dog biscuit having a water activity of 0.70 or less.

42. A baked dog or cat biscuit as claimed in claim 41 wherein the at least one alkali metal inorganic pyrophosphate is tetrasodium pyrophosphate.

43. A baked dog or cat biscuit as claimed in claim 41 wherein the at least one alkali metal inorganic pyrophosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

44. Raw hide having a coating containing a tartar-control effective amount of at least one inorganic pyrophosphate compound.

45. The raw hide as claimed in claim 44 wherein the raw hide is in strip form.

46. The raw hide as claimed in claim 44 wherein the inorganic pyrophosphate is an alkali metal pyrophosphate.

47. The raw hide as claimed in claim 46 wherein the alkali metal pyrophosphate is tetrasodium pyrophosphate.

48. The raw hide as claimed in claim 44 wherein the at least one inorganic pyrophosphate is a combination of at least one trialkali metal monoacid pyrophosphate and at least one tetraalkali metal pyrophosphate.

49. Process for preparing raw hide having a coating comprising a tartar control effective amount of at least one water soluble, alkali metal, inorganic pyrophosphate compound, comprising:
(a) contacting raw hide with a viscous liquefied coating material containing at least one water soluble, alkali metal, inorganic pyrophosphate compound, thereby, forming a coating of said liquefied coating material on the raw hide; and (b) drying the raw hide having a coating containing a tartar control effective amount of at least one water soluble, alkali metal, inorganic pyrophosphate compound.

50. The process as claimed in claim 49 wherein the coat-ing material contains about 0.1 to about 10 weight percent of said at least one water soluble, alkali metal, inorganic pyrophosphate compound, and the drying is conducted at 75° to 300°F.

51. The process a claimed in claim 49 wherein the coating material contains about 0.25 to about 5 weight percent of said at least one water soluble, alkali metal, inorganic pyrophosphate compound.

52. The process as claimed in claim 49 wherein the at least one water soluble, alkali metal, inorganic phosphate is a combination of trisodium monoacid pyrophosphate and tetrapotassium pyrophosphate.

53. The process as claimed in claim 49 wherein the raw hide, in the form of a relatively long rope, is dipped into the solution of at least one water soluble, alkali metal, inorganic pyrophosphate, air dried and cut into strips.