WO2010051352A2

WO2010051352A2 - Microbiocidal compositions and their preparation and use

Info

Publication number: WO2010051352A2
Application number: PCT/US2009/062509
Authority: WO
Inventors: Dean A. Danilson; Robert Pershon; Eric W. Liimatta
Original assignee: Albemarle Corporation
Priority date: 2008-10-31
Filing date: 2009-10-29
Publication date: 2010-05-06
Also published as: PE20110295A1; WO2010051352A3; AR075656A1

Abstract

Frozen microbiocidal compositions which comprise a frozen aqueous microbiocidal solution containing a bromine content from at least one 1,3-dibromo-5,5-dialkylhydantoin are described. Methods of producing such compositions and methods for making use of such compositions are also described. Among the advantages are that the water resulting from melting of the frozen compositions typically has microbiocidal activity. Thus, in effect, during refrigerated storage, during ensuing refrigerated transportation, and during ensuing usage at retail distribution points the water from the melted ice not only has protected the foodstuff, but sanitizes surfaces associated therewith.

Description

MICROBIOCIDAL COMPOSITIONS AND THEIR PREPARATION AND USE

TECHNICAL FIELD

[0001] This invention relates to new ways of, and new compositions for, protecting fresh and/or frozen foodstuffs for consumption by humans or animals, especially fresh and/or frozen meat, seafood, shellfish, poultry, fruit, and vegetables, as well as other perishable foodstuffs from spoilage during various periods of transportation and/or storage.

BACKGROUND

[0002] Many foodstuffs intended for human or animal consumption, including fresh meat, fish, and poultry are exposed to periods during which microbial populations can form and flourish thereon. For example raw (i.e. , uncooked) meat, fish, and poultry are often placed on display for sale in commercial markets and in neighborhood stores or supermarkets. Often these foods are kept chilled by refrigeration or by use of ice in order to reduce the rate at which proliferation of microorganisms occurs on them. Nevertheless, at best these methods of chilling do not prevent proliferation of microbial growth. Instead, the rate of microbial growth is merely reduced to what has been generally considered a tolerable level. [0003] Heretofore it has been proposed to provide ice containing certain chemical species that generate chlorine dioxide gas in ice, which frozen composition is proposed for use in contact with surfaces of food. According to U.S. Pat. No. 6,120,731, speaking as of its filing date in February 1999:

(A) "A recent Food Additive Petition has been made to the U.S. Food & Drug Administration, in which the commercial use of ice containing chlorine dioxide has been requested (Bio-Cide International, Inc., Food Additive Petition 6A4499, filed May 8, 1996). The preparation of such ice is somewhat tedious, and potentially dangerous with respect to the inhalation of high levels of chlorine dioxide from the initial concentrates. These concentrates are prepared, for example, from a combination of 10% citric acid and 2.0% aqueous sodium chlorite solution, which results in upwards of 5, 000 parts per million (ppm) of chlorine dioxide in the solution. The solution is then diluted with water so that the final concentration of chlorine dioxide plus sodium chlorite is no more than about 25 ppm, which liquid is then frozen. Since the permitted level for continuous exposure of factory workers to chlorine dioxide is only 0.1 ppm in the air, and since chlorine dioxide is a volatile gas, such preparation and use is potentially problematic, as well as expensive.

(B) "However, one of the advantages of chlorine dioxide is that, as a gas, it can escape from frozen or re-liquefied water and permeate the surfaces of food to reduce their microbial loading. To this end, the use of chlorine dioxide- impregnated ice would be particularly advantageous for the storage of fish and shellfish after harvesting. Fish, particularly in tropical areas, can spoil within hours at ambient temperatures because bacteria on their surfaces multiply rapidly and invade the tissues. The putrefaction that results from such proliferation, as well as degradative biochemical processes, could well be suppressed by the use of ice containing chlorine dioxide. However, the large quantities of ice that would be needed would be prohibitively expensive if prepared by the activation/dilution process that is currently under development."

[0004] Although U.S. Pat. No. 6,120,731 proposed simpler and more cost-effective techniques for producing chlorine dioxide-containing ice, the fact remains that, as the patent acknowledges, chlorine dioxide gas is potentially dangerous with respect to inhalation. Moreover, being a gas, chlorine dioxide is indicated to be able to permeate the surfaces of the food and thus can be entrapped or otherwise occluded within the interior fleshy portions of the meat, fish, or poultry. [0005] A need thus exists for a new way of significantly reducing the rate of microbial proliferation on chilled foods including meat, fish, and poultry, especially during storage, transportation, and/or when they are on display for sale. In addition, it would be especially desirable if this new way could avoid use of a material that releases a potentially dangerous level of gas during manufacture or use of the material. [0006] This invention is believed to fulfill the foregoing need in an especially desirable way.

BRIEF SUMMARY OF THE INVENTION

[0007] This invention is based on the discoveries, inter alia, that l,3-dibromo-5,5- dimethylhydantoin provides chemical species when dissolved in water which are able to survive the freezing and thawing processes as applied to the solution, and that the frozen aqueous microbiocidal solution is exceptionally effective in reducing the rate of microbial proliferation on chilled food such as fresh poultry meat. In practice, there are at least two temperature-dependent ways in which the frozen solutions of this invention may function. First of all, when the foodstuff is in contact with the frozen solution at temperatures enabling the ice to gradually melt, the rate of microbial proliferation is reduced by the combination of the chilling effect of the frozen solution and the timed release of aqueous activated solution from the frozen solution as it slowly thaws. On the other hand, when the foodstuff is in contact with the frozen solution at temperatures below the thawing temperature of the frozen solution, (e.g., when low temperature refrigeration is being employed along with the frozen solution) the frozen solution can contribute to the spoilage-reducing effect of the chilling until the temperature is reached at which the frozen solution commences to thaw. At that point, thawed solution is released which then exerts its effects in retarding spoilage of the foodstuff. In this latter case, the temperature increase is preferably effected by reducing the extent of refrigeration of the system so that the frozen solution can begin to thaw. In some cases, however, heat generated by localized bacterial action may raise localized temperatures sufficiently for some of the frozen solution to begin thawing so that the thawed solution can begin exerting its beneficial antimicrobial effects upon the foodstuff. [0008] It is surprising that the freezing process and the thawing process do not materially degrade the bromine content of ice prepared from an aqueous solution of l,3-dibromo-5,5- dimethylhydantoin because one of the weaknesses of oxidizing biocides is that in many situations they decay before they are applied to the desired application. As used herein, including the claims, the term "bromine content" relates to the total amount of bromine present as determined by Hach DPD Method 8016 using the DPD indicator powder containing potassium iodide, which method is described in the Hach Water Analysis Handbook, 3rd edition, copyright 1997, Hach Company, Loveland, Colorado. A description of the method is also set forth hereinafter. [0009] Accordingly, this invention provides in one of its embodiments a frozen microbiocidal composition which comprises a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5-dialkylhydantoin that was dissolved in water, said at least one l,3-dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms. As used herein, the terms "frozen microbiocidal composition", whether in the singular or plural, and "frozen aqueous microbiocidal solution", whether in the singular or plural, are used interchangeably. Thus, no distinction as between or among these terms intended or is to be inferred. [0010] Another embodiment of this invention is a method of producing a microbiocidal composition for providing increased microbiocidal protection to foodstuffs, which method comprises freezing an aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5-dialkylhydantoin that was dissolved in water, said at least one 1,3- dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms. A preferred embodiment of this embodiment comprises placing frozen aqueous microbiocidal solution containing a bromine content formed by such freezing into contact with a foodstuff at a temperature enabling the frozen aqueous microbiocidal solution to melt and thereby form liquid aqueous microbiocidal solution from the frozen aqueous microbiocidal solution and is contacted by aqueous microbiocidal solution formed by the melting of such frozen aqueous microbiocidal solution. Consequently, the foodstuff will be cooled by the frozen aqueous microbiocidal solution and will be contacted by the aqueous solution having bacteriocidal or bacteriostatic activity, or both such activities, as aqueous solution is released by thawing from the frozen solution, thereby protecting the foodstuff against spoilage. In the practice of this embodiment, multiple additions of the frozen aqueous microbiocidal solution can be made either periodically or as needed to the foodstuff being protected, thereby providing increased shelf life for the foodstuff. The rate at which such additions are made will of course depend upon the temperature of the environment and the quantity of the frozen aqueous microbiocidal solution being employed relative to the amount of foodstuff being protected. Typically, the amount of frozen aqueous microbiocidal solution employed in a given batch of foodstuff should be sufficient to provide protection to the foodstuff for a period of at least about 8 hours prior to replenishment, as this will reduce the effort required if more frequent replenishment is utilized. [0011] The frozen aqueous microbiocidal solutions of this invention are capable of disinfecting the foodstuff, increasing the shelf life of the foodstuff, and reducing spoilage of the foodstuff. Thus, still another embodiment of this invention is a method of disinfecting foodstuffs, and/or increasing the shelf life of foodstuffs, and/or reducing spoilage of foodstuffs, which method comprises maintaining the foodstuff in contact with:

(A) a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5-dialkylhydantoin that was dissolved in water, said at least one l,3-dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms;

(B) water which in turn is in contact with frozen aqueous microbiocidal solution of (A), or

(C) both the aforesaid frozen aqueous microbiocidal solution of (A) and water which is in contact with the frozen aqueous microbiocidal solution of (A).

[0012] Yet another embodiment of this invention is a method of reducing microbial contamination and spoilage of a perishable food product, which method comprises:

A) packing a food product with a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5-dialkylhydantoin that was dissolved in water, so that the food product is in contact with said frozen aqueous microbiocidal solution, said at least one l,3-dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms; and

B) storing said perishable food product packed with said frozen aqueous microbiocidal solution at a temperature that allows said frozen aqueous microbiocidal solution to melt and thereby form liquid aqueous microbiocidal solution from the frozen aqueous microbiocidal solution so that the foodstuff is cooled by the frozen aqueous microbiocidal solution and is contacted by liquid aqueous microbiocidal solution formed by the melting of such frozen aqueous microbiocidal solution.

[0013] One of the additional features and advantages of this invention is the ability of the compositions of this invention to provide continuous or continual microbiocidal and/or microbiostatic activity on a time-release basis to foodstuff in contact with the composition as at least a portion of the composition is allowed to thaw over time.

[0014] Still another feature of this invention is the discovery that in preparing the frozen aqueous microbiocidal solutions of this invention, it is desirable to conduct the freezing process with the aqueous microbiocidal solution in a substantially static condition. [0015] A further embodiment is a method of controlling microbial contamination and spoilage of a perishable food product, which method comprises placing at least one perishable food product in contact with a body or mass of frozen aqueous solution of at least one 1,3- dibromo-5,5-dialkylhydantoin and enabling or causing the frozen aqueous solution to melt at a rate in the range of about 500 mg to about 20 g of melted solution per kilogram of meat while in contact with said food product. Practice of this embodiment results in inhibition of reestablishment and/or regrowth of microbial colonies during the period said body or mass of aqueous solution is melting. [0016] These and other embodiments and/or features of this invention will become still further apparent from the ensuing description and appended claims.

FURTHER DETAILED DESCRIPTION OF EMBODIMENTS OF THIS

INVENTION [0017] The l,3-dibromo-5,5-dialkylhydantoins used in the practice of this invention are normally solid materials which have low solubilities in water and which do not release significant adverse levels of any gaseous components from their aqueous solutions. For example, the preferred l,3-dibromo-5,5-dialkylhydantoin is l,3-dibromo-5,5- dimethylhydantoin, which is reported to have a water solubility of only 405 ppm expressed as Cl₂ at 75⁰F (ca. 24⁰C). Such low solubilities in water make possible the formation of dilute aqueous solutions which, in test work described hereinafter, have been found to resist decay or degradation during the freezing and thawing process and which render the ice highly effective as a microbiocidal composition while functioning at the cold temperatures provided by the ice. [0018] The microbiocidal compositions of this invention comprise a frozen aqueous microbiocidal solution comprised of a bromine content derived from and produced by freezing an aqueous solution formed from water and at least one l,3-dibromo-5,5-dialkylhydantoin in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to 4 carbon atoms. [0019] Preferred microbiocides used in forming these microbiocidal compositions include such compounds as l,3-dibromo-5,5-dimethylhydantoin, l,3-dibromo-5-ethyl-5- methylhydantoin, 1 ,3-dibromo-5-n-propyl-5-methylhydantoin, 1 ,3-dibromo-5-isopropyl-5- methylhydantoin, 1 ,3-dibromo-5-ra-butyl-5-methylhydantoin, 1 ,3-dibromo-5-isobutyl-5- methylhydantoin, 1 ,3-dibromo-5-sec-butyl-5-methylhydantoin, 1 ,3-dibromo-5-tert-butyl-5- methylhydantoin, and mixtures of any two or more of them. Of these biocidal agents, 1,3- dibromo-5-isobutyl-5-methylhydantoin, l,3-dibromo-5-n-propyl-5-methylhydantoin, and 1,3- dibromo-5-ethyl-5-methylhydantoin are, respectively, preferred, more preferred, and even more preferred members of this group from the cost effectiveness standpoint. Of the mixtures of the foregoing biocides that can be used pursuant to this invention, it is preferred to use 1,3- dibromo-5,5-dimethylhydantoin as one of the components, with a mixture of l,3-dibromo-5,5- dimethylhydantoin and 1 ,3-dibromo-5-ethyl-5-methylhydantoin being particularly preferred.

The most preferred member of this group of microbiocides is l,3-dibromo-5,5- dimethylhydantoin. This compound is available in the marketplace under the trade designation BROMITIZE^® biocide (Solution BioSciences, Inc.) and in tablet or granular form under the trade designations Albrom^® IOOT biocide and Albrom^® IOOPC biocide (Albemarle Corporation).

[0020] When a mixture of two or more of the foregoing 1 ,3-dibromo-5,5-dialkylhydantoin biocides is used pursuant to this invention, the individual biocides of the mixture can be in any proportions relative to each other.

[0021] Methods for producing the l,3-dibromo-5,5-dialkylhydantoins utilized pursuant to this invention are known and reported in the literature. See, for example, U.S. Pat. No.

6,809,205.

[0022] To prepare the aqueous solutions, which are frozen pursuant to this invention, water and one or more selected l,3-dibromo-5,5-dialkylhydantoins are brought together to form a solution. The amount of the 1 ,3-dibromo-5,5-dialkylhydantoin(s) used is an amount sufficient to provide microbiocidal activity, i.e., an effective microbiocidal amount is used. Typically, such amount is a bromine content of at least about 15 ppm (wt/wt) in the water prior to freezing. Bromine contents in the range, on a weight basis, of about 20 ppm to about 200 ppm prior to freezing are typical. Bromine contents in the range of about 40 to about 100 ppm (wt/wt) prior to freezing are preferred. Since the water solubilities of the l,3-dibromo-5,5- dialkylhydantoins varies from compound to compound, the amount used will ordinarily not exceed an amount that dissolves in the water at room temperature. If however, precipitate formation occurs when forming the solution, the solids can be removed by filtration or like physical separation procedures. The aqueous solution of the l,3-dibromo-5,5- dialkylhydantoin(s) is then frozen into whatever physical form or shape desired. Such forms or shapes can include slabs, blocks, cubes, and/or other geometric shapes. Shavings, granules, or the like, can be readily produced from larger physical forms of the frozen solution by known methods. As noted above, the method used for freezing may affect the bromine content in the water formed on thawing of the ice. Thus, in any situation where the extent of diminution of bromine content during the freezing and thawing process has not been established, it is desirable to melt a representative portion of the frozen aqueous microbiocidal solution and determine its bromine content. Generally speaking, the amount of diminution of bromine content should not be more than about 100 ppm on a weight basis. It should be noted that all ppm values given in this paragraph are values determined by use of the Hach DPD Method 8016 referred to above and hereinafter, in which potassium iodide is employed as one of the components used in the procedure. [0023] Generally speaking, it is desirable to form and ship larger physical forms of the frozen solution to the point of usage, at which point the larger physical form can be reduced in size such as shavings, small chunks, snow, granules, or the like, for application to the food to be protected against rapid spoilage. In the cases of storage and shipment of suitable types of foodstuffs it is also desirable to embed the foodstuff within the aqueous solution of the 1,3- dibromo-5,5-dialkylhydantoin(s) and to promptly freeze the solution containing the embedded foodstuff within the confines of the resultant frozen article, such as a block or slab of the microbiocidal ice containing one or more embedded articles of foodstuff. Such blocks or slabs can then be maintained under refrigeration during storage and shipment to the points of retail distribution. [0024] Alternatively, the frozen solutions used pursuant to this invention can be formed at the site of the food to be protected against rapid spoilage, and promptly after formation can be applied to the foodstuff. If this location is at a central distribution point, such as a central fish or meat market, the combination of the frozen composition of this invention and the foodstuff can be shipped together to the local points of sale, such as local stores and supermarkets. On the other hand, if this location is on the premises of the local point of sale such as at a supermarket, no such transportation or shipment is required. Rather, the appropriate physical form of the frozen microbiocidal composition of this invention can be formed and promptly placed into contact with the particular foodstuff or foodstuffs to be protected. [0025] If desired, the frozen microbiocidal compositions of this invention can be produced by concurrently or substantially concurrently forming a solution of the l,3-dibromo-5,5- dialkylhydantoin(s) and freezing such solution. For example, the water initially may be refrigerated so as to be slightly above the freezing point and the solution can be formed from such chilled water, which then is promptly frozen into the desired physical form(s). [0026] As noted above, a feature of this invention is the discovery that the manner in which the freezing process in conducted can have an effect upon the efficacy of the resultant frozen composition. Typically, it is desirable to freeze the aqueous solution of the l,3-dibromo-5,5- dialkylhydantoin(s) while the solution is in a substantially static condition. If, on the other hand, the freezing is conducted by utilizing a system in which the liquid is not in a substantially static condition, such as a shell and tube freezing system, the resultant ice, on thawing, will initially release water having a lower concentration than the concentration used in making the solution. As a consequence, the microbiocidal and/or microbiostatic water released from the ice will, at least for a period of time, contain variable concentrations of the active microbiocidal and/or microbiostatic constituents. On the other hand, when forming the frozen aqueous microbiocidal solutions of this invention by freezing a solution of the aqueous solution of the l,3-dibromo-5,5-dialkylhydantoin(s) while in a substantially static condition, the microbiocidal and/or microbiostatic water released from the ice will have a more uniform concentration of its active microbiocidal and/or microbiostatic components as released over a period of time. By substantially static in this context it is meant that the state of the solution to be frozen, as it is being frozen, is in a quiescent state. An example of a quiescent state would be the state of water placed in a ice cube tray be while stored in a conventional refrigerator. [0027] One typical way of utilizing the frozen aqueous microbiocidal solutions of this invention is to pack or otherwise place the foodstuff into direct contact with the frozen aqueous microbiocidal solution. For example, the foodstuff can be placed onto a layer of subdivided frozen aqueous microbiocidal solution in the form of shavings, chips, chunks, etc., or onto a block or slab of non- subdivided frozen aqueous microbiocidal solution. Similarly, the foodstuff can be packed or encased partially or wholly within a bed of subdivided frozen aqueous microbiocidal solution in the form of shavings, chips, chunks, etc., or partially or wholly between or among blocks or slabs of non- subdivided frozen aqueous microbiocidal solution. Combinations of subdivided and non- subdivided frozen aqueous microbiocidal solution can also be employed, such as, for example, by placing the foodstuff onto a slab of non- subdivided microbiocidal solution and then either covering or surrounding the foodstuff with subdivided microbiocidal solution.

[0028] Another convenient way of utilizing the frozen aqueous microbiocidal solutions of this invention is to place suitable forms of them (e.g., blocks, chunks, cubes, or etc.) into contact with water in order to reduce the temperature of the water to temperatures somewhat above the freezing point. At the same time, the microbiocidally- active bromine content of the frozen microbiocidal composition will become dissolved in the water as the frozen microbiocidal composition partially melts. In this way, the water containing the dissolved microbiocidally-active bromine content can be placed into contact with the foodstuff to be sanitized or disinfected. In utilizing this technique, it is desirable to ensure that the initial frozen microbiocidal composition has a sufficiently high concentration of the 1,3-dibromo- 5,5-dialkylhydantoin(s) to contribute an appropriate microbiocidal concentration to the water to which the frozen microbiocidal composition has been added. [0029] Any of a wide variety of foodstuffs normally susceptible to spoilage during storage, shipment, or display can be protected by use of the frozen microbiocidal compositions of this invention. As noted above, the foodstuff and the frozen microbiocidal composition of this invention are brought into contact with each other. In this connection, such contact can be (i) between the frozen microbiocidal composition and the foodstuff or (ii) between the foodstuff and chilled water in contact with the frozen microbiocidal composition, or (iii) between and among (a) the foodstuff, (b) the frozen microbiocidal composition, and (c) water in contact with the frozen microbiocidal composition.

[0030] A few non-limiting examples of foodstuffs that can be protected from spoilage by the practice of this invention include edible meat from any of a variety of meat-producing animals, non-limiting examples of which include beef, pork, mutton, venison, poultry, turkey, lamb, veal, wild game, and other similar edible meats; edible fish including edible fish that are caught or harvested from the sea (oceans, bays, etc.), lakes or streams, or from land based fish farms, and also including shellfish, crustaceans, eels, octopus, squid, and similar edible seafoods; and edible fruits and vegetables. The foodstuff being treated pursuant to this invention can be in various forms such as butchered raw meats as formed at the slaughterhouse or meat packing facility, butchered cuts of raw meat, ground raw meats, whole raw fish, eviscerated raw fish, raw fillets of fish, shucked or peeled seafood, and fruits and vegetables that are whole, diced, sliced, peeled, chopped, or shredded. [0031] Although it is possible and within the scope of this invention to include other components in the aqueous microbiocidal solutions frozen pursuant to this invention, such as surfactants, stabilizers, other microbiocides, buffers, or the like, the advantages of this invention can be achieved without use of such ancillary components. Indeed, a preferred embodiment of this invention is that the frozen compositions of this invention are produced from aqueous solutions which are devoid of any added dissolved component other than the bromine content formed from one or more l,3-dibromo-5,5-dialkylhydantoins described herein and any soluble residues of any component that may have been added to the water supply by the water supplier for public health reasons such as fluorination/fluoridation for enhanced dental health. In this connection, it is even more preferred to employ in the practice of this invention, a source of water that is devoid of any such other components, e.g. , distilled water or deionized water. [0032] The standard method for determining bromine content used herein is commonly known as the DPD test procedure 8016. This method is well suited for determining very small bromine contents in aqueous systems. The standard DPD test for determining such low levels of bromine content is based on classical test procedures devised by Palin in 1974. See A. T. Palin, "Analytical Control of Water Disinfection With Special Reference to Differential DPD Methods For Chlorine, Chlorine Dioxide, Bromine, Iodine and Ozone", /. Inst. Water Eng., 1974, 28, 139. While there are various modernized versions of the Palin procedures, the recommended version of the test is fully described in Hach Water Analysis Handbook, 3rd edition, copyright 1997, Hach Company, Loveland, Colorado. The procedure for "total chlorine" is identified in that publication as Method 8167 appearing on page 379. Briefly, the "total chlorine" test involves introducing to the dilute water sample containing active halogen, a powder comprising DPD indicator powder, (L e. , N,N'-diethyldiphenylenediamine), KI, and a buffer. The active halogen species present react(s) with KI to yield iodine species which turn the DPD indicator to red/pink. The intensity of the coloration depends upon the concentration of "total chlorine" species present in the sample. This intensity is measured by a colorimeter calibrated to transform the intensity reading into a "total chlorine" value in terms of mg/L Cl₂.

If the halogen content present is a bromine content, the result in terms of mg/L Cl₂ is multiplied by 2.25 to express the result in terms of mg/L Br₂ of active bromine. [0033] In greater detail, the DPD test procedure is as follows:

1) To determine the amount of species present in the water which respond to the "total chlorine" test, the water sample should be analyzed within a few minutes of being taken, and preferably immediately upon being taken.

2) Hach Method 8167 for testing the amount of species present in the water sample which respond to the "total chlorine" test involves use of the Hach Model DR 2010 colorimeter. The stored program number for chlorine determinations is recalled by keying in "80" on the keyboard, followed by setting the absorbance wavelength to 530 nm by rotating the dial on the side of the instrument. Two identical sample cells are filled to the 10 mL mark with the water under investigation. One of the cells is arbitrarily chosen to be the blank. To the second cell, the contents of a DPD Total

Chlorine Powder Pillow are added. This is shaken for 10-20 seconds to mix, as the development of a pink-red color indicates the presence of species in the water which respond positively to the DPD "total chlorine" test reagent. On the keypad, the SHIFT TIMER keys are depressed to commence a three minute reaction time. After three minutes the instrument beeps to signal the reaction is complete. Using the 10 mL cell riser, the blank sample cell is admitted to the sample compartment of the Hach Model DR 2010, and the shield is closed to prevent stray light effects. Then the ZERO key is depressed. After a few seconds, the display registers 0.00 mg/L Cl₂. Then, the blank sample cell used to zero the instrument is removed from the cell compartment of the

Hach Model DR 2010 and replaced with the test sample to which the DPD "total chlorine" test reagent was added. The light shield is then closed as was done for the blank, and the READ key is depressed. The result, in mg/L Cl₂ is shown on the display within a few seconds. This is the "total chlorine" level of the water sample under investigation. By multiplying this value by 2.25, the level of active bromine in the water sample is provided. It is to be noted that by dialing in "50" instead of "80" on the keyboard, the instrument displays the result in mg/L Br₂ automatically. In other words, the multiplication by 2.25 is unnecessary if key "50" is utilized. [0034] The frozen compositions of this invention can be used for killing, or at least controlling, motile and non-motile bacteria such as for example Escherichia coli, Salmonella enteritidis, Salmonella typhimurim, Campylobacter jejuni, Campylobacter coli,

Campylobacter lari, and bacteria in the form of biofilms such as for example Listeria monocytogenes, Pseudomonasfluorescens, Pseudomonas aeruginosa, Enterococcus faecium, and Staphylococcus aureus.

[0035] Another advantage of this invention is that upon melting, the frozen microbiocidal compositions of this invention yield water that has microbiocidal or sanitizing activity which remains primarily in the water rather than escaping as a gas. This water in turn comes in contact with and thus disinfects various surfaces often in contact with the foodstuff, as well as other surfaces, pipelines, etc. which become contacted with melted portions of the aqueous microbiocidal compositions of this invention. Thus, in effect, the frozen microbiocidal compositions of this invention can provide microbiocidal activity to surfaces as well as foodstuffs during refrigerated storage, during ensuing refrigerated transportation, and during ensuing usage at retail distribution points. Moreover, the final aqueous effluents are environmentally friendly.

[0036] The following examples are presented to illustrate the efficacy of this invention. These examples are not intended to limit the invention to only the subject matter described therein.

EXAMPLE l

[0037] Experiments were carried out to determine whether a l,3-dibromo-5,5- dialkylhydantoin could be frozen without substantial loss of its bromine content on freezing. In these experiments, three stock solutions were prepared by dissolving l,3-dibromo-5,5- dimethylhydantoin in water, diluting with deionized water and determining the bromine content in the respective stock solutions using the standard HACH method of analysis, viz., Method 8016. Four samples of each of these three stock solutions were then frozen while in a substantially static (e.g., quiescent) state in the freezing compartment of a refrigerator for a period of at least 12 hours and then were allowed to thaw at room temperature. The bromine contents in the thawed aqueous test samples were then measured by the standard HACH method. The results of these tests are summarized in Table 1.

TABLE 1

*Total bromine content as determined by Hach method 8016 using DPD, KI, and buffer.

EXAMPLE 2

[0038] In these experiments, normal poultry after it came out of the chill tanks was used in the test work. The bird carcasses were put in two groups with one group having untreated ice and the other group having ice made by freezing water, to which had been added 1 ,3-dibromo- 5,5-dimethylhydantoin (DBDMH), having a nominal bromine content of 85 ppm. The respective test ice samples were placed in separate insulated cardboard containers and the carcasses were placed in either a container containing the DBDMH treated ice or untreated ice. These containers were stored at 35⁰F, and at designated time points, carcasses were removed from the container and subjected to a whole bird carcass rinse to determine the level of bacteria present. Determinations were made related to the respective counts of aerobic plate count bacteria (APC bacteria) and of pyschotropic (cold loving) bacteria. Unfortunately, an inadequate supply of ice was initially prepared and thus, only the results up to 8 days of storage gave results of significance. Thereafter, because of the inadequate quantity of DBDMH treated ice, the bacterial counts in all samples rose dramatically. Nevertheless, the results for day 8 showed that product stored on DBDMH-treated ice averaged 60 cfu/g for aerobic plate count bacteria and 400 cfu/g for psychotrophs (cold loving bacteria). In contrast, poultry carcasses stored on regular ice after day 8 averaged 7,400 cfu/g for APC bacteria and 76,940 cfu/g for psychotrophs.

EXAMPLE 3

[0039] A shelf-life study of eviscerated whole bird carcasses stored refrigerated in tubs containing DBDMH treated ice or non-treated ice. The evaluation utilized whole bird rinsing of the eviscerated carcasses to determine aerobic plate count (APC) and psychotropic plate count (PPC) to compare bacterial loads on the eviscerated birds stored in ice made from water treated with DBDMH verses non-treated ice during the shelf-life expectancy. The ice treated with DBDMH was formed by freezing water with which had been blended approximately 95 ppm (wt/wt) of DBDMH. The experimental methods employed involved use of a more detailed test protocol to ensure reliable plate count results after periods of storage in contact with either type of ice utilized in the study. Table 2 summarizes the comparative raw data on

APC and PPC obtained in this test. Table 2

[0040] Comparative organoleptic testing of cooked meat from treated carcasses on day 1 and on day 5 gave inconclusive results.

[0041] Further embodiments of the invention include, without limitation:

[0042] A) A method of controlling microbial contamination and spoilage of a perishable food product, which method comprises placing at least one perishable food product in contact with a body or mass of frozen aqueous solution of at least one l,3-dibromo-5,5- dialkylhydantoin and enabling or causing the frozen aqueous solution to melt at a rate in the range of about 500 mg to about 20 g of melted solution per kilogram of meat while in contact with said food product .

[0043] B) A method as in A), wherein said body or mass of frozen aqueous solution is periodically replenished with fresh frozen aqueous solution of at least one l,3-dibromo-5,5- dialkylhydantoin, so as to maintain perishable food product in contact with a body or mass of frozen aqueous solution of at least one 1 ,3-dibromo-5,5-dialkylhydantoin for a period of at least about 24 hours.

[0044] C) A method as in A), wherein said body or mass of frozen aqueous solution is in the form of a plurality of shapes at least 80% by weight of which are of a size in which the largest dimension of each of the individual shapes is about 2 inches or less.

[0045] D) A method as in C), wherein said plurality of shapes when brought into contact with said food product, is comprised of at least one form of shape selected from cubes, shavings, granules, chunks, chips, pellets, grains, particles, lumps, fragments, flakes, slivers, and miscellaneous shapes.

[0046] Components referred to by chemical name or formula anywhere in the specification or claims hereof, whether referred to in the singular or plural, are identified as they exist prior to coming into contact with another substance referred to by chemical name or chemical type (e.g. , another component, a solvent, or etc.). It matters not what chemical changes, transformations and/or reactions, if any, take place in the resulting mixture or solution as such changes, transformations, and/or reactions are the natural result of bringing the specified components together under the conditions called for pursuant to this disclosure. Thus the components are identified as ingredients to be brought together in connection with performing a desired operation or in forming a desired composition. Also, even though the claims hereinafter may refer to substances, components and/or ingredients in the present tense ("comprises", "is", etc.), the reference is to the substance, component or ingredient as it existed at the time just before it was first contacted, blended or mixed with one or more other substances, components and/or ingredients in accordance with the present disclosure. The fact that a substance, component or ingredient may have lost its original identity through a chemical reaction or transformation during the course of contacting, blending or mixing operations, if conducted in accordance with this disclosure and with ordinary skill of a chemist, is thus of no practical concern. [0047] Each and every patent or publication referred to in any portion of this specification is incorporated in toto into this disclosure by reference, as if fully set forth herein. [0048] The invention may comprise, consist or consist essentially of the materials and/or procedures recited herein.

[0049] As used herein, the term "about" modifying the quantity of an ingredient in the compositions of the invention or employed in the methods of the invention refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term about also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term "about", the claims include equivalents to the quantities.

[0050] Antimicrobial compositions can affect two kinds of microbial cell damage. The first is a lethal, irreversible action resulting in complete microbial cell destruction or incapacitation. The second type of cell damage is reversible, such that if the organism is rendered free of the agent, it can again multiply. The former can be termed bacteriocidal and the latter, bacteriostatic. A sanitizer and a disinfectant can be regarded as agents which provide antibacterial or bacteriocidal activity. On the other hand, an inhibitor or bacteriostatic composition may be regarded as a preservative. For the purposes of this invention, either type of activity is deemed advantageous, especially in cases where increased shelf life is achieved. [0051] Thus, as used herein, the term "microbiocidal" is used in the same sense as the word "bacteriocidal"; similarly, the term "microbiostatic" is used in the same sense as the word "bacteriostatic".

[0052] This invention is susceptible to considerable variation in its practice. Therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.

Claims

CLAIMS:

1. A frozen microbiocidal composition which comprises a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water to form such solution, said at least one 1,3- dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms.

2. A composition as in Claim 1 wherein said at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water comprised l,3-dibromo-5,5-dimethylhydantoin.

3. A composition as in Claim 1 wherein said at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water consisted of l,3-dibromo-5,5-dimethylhydantoin.

4. A composition as in any of Claims 1-3 wherein said frozen aqueous microbiocidal solution is in the form of blocks, slabs, chunks, cubes, shavings, or granules (a) sized to be suitable for being in contact with foodstuffs and (b) having the capability of providing increased microbiocidal protection to foodstuffs (i) in contact therewith or (ii) embedded therein, or (iii) both of (i) and (ii).

5. A method of producing a microbiocidal composition for providing increased microbiocidal protection to foodstuffs, which method comprises freezing an aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water to form such solution, said at least one 1,3- dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms.

6. A method as in Claim 5 further comprising placing frozen aqueous microbiocidal solution containing a bromine content formed by said freezing into contact with a foodstuff at a temperature enabling said frozen aqueous microbiocidal solution to melt and thereby form liquid aqueous microbiocidal solution from the frozen aqueous microbiocidal solution, so that the foodstuff is cooled by the frozen aqueous microbiocidal solution and is contacted by aqueous microbiocidal solution formed by the melting of such frozen aqueous microbiocidal solution.

7. A method of sanitizing and/or disinfecting foodstuffs, which method comprises maintaining the foodstuff in contact with: (A) a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5-dialkylhydantoin that was dissolved in water, said at least one 1,3- dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms;

8. A method of reducing microbial contamination and spoilage of a perishable food product, which method comprises:

A) packing around a food product, a frozen aqueous microbiocidal solution containing a bromine content from at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water, so that the surface of the food product is in contact with said frozen aqueous microbiocidal solution, said at least one l,3-dibromo-5,5-dialkylhydantoin, prior to dissolution in the water, being one in which one of the alkyl groups is a methyl group and the other alkyl group contains in the range of 1 to about 4 carbon atoms; and

9. A method as in Claim 8 wherein in B) said water so produced is enabled or caused to contact and sanitize both (i) surfaces associated with said frozen aqueous microbiocidal solution, and (ii) surfaces downstream from said surfaces that said water contacts.

10. A method as in any of Claims 5-9 wherein said at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water comprised l,3-dibromo-5,5-dimethylhydantoin.

11. A method as in any of Claims 5-9 wherein said at least one l,3-dibromo-5,5- dialkylhydantoin that was dissolved in water consisted of l,3-dibromo-5,5-dimethylhydantoin.

12. A method as in any of Claims 5-9 wherein the foodstuffs that are sanitized and/or disinfected comprise uncooked seafood or uncooked meat, or both.