GB1593996A - Controllably moisturized large size tubular cellulosic food casings - Google Patents

Abstract

The casing used is a tubular cellulosic casing comprising a coated fibrous core in its wall. In the stuffed state, its maximum diameter is between 40 and 200 mm. So that the internal pressure to which it is subjected reaches a multiple of from 1.4 to 4 times the value which would cause if it to attain its dimensions corresponding to complete stuffing if it were totally saturated with moisture, the moisture content of the casing is limited to the range of from 25 to 71 % by weight relative to the dry cellulose in the casing. This casing is particularly suitable for manufacturing sausages.

Description

(54) CONTROLLABLY MOISTURIZED LARGE SIZE TUBULAR CELLULOSIC FOOD CASINGS (71) We, UNION CARBIDE CORPORATION, a corporation organized and existing under the laws of the State of New York, United States of America, whose registered office is 270 Park Avenue, New York, State of New York 10017, United States of America (assignee of JOHN HELLER BACKMAN), do hereby declare the invention, for which we pray that a patent may be granted to us, and the, method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to fibrous tubular cellulosic food casings.

Food casings are used throughout the world in the processing of a great variety of meat and other food products, such as sausages of various types, cheese rolls, turkey rolls, and the like. Casings most generally used are synthetic tubular food casings prepared from regenerated cellulose and other cellulosic materials, which are of different types and sizes to accommodate the various categories of food products comprehended. Tubular food casings are provided in supported or unsupported form with supported casings, commonly referred to as "fibrous casings," being prepared with a fibrous support web embedded in the walls thereof.

A common feature of most processed food products, particularly meat products, is that the mixture of ingredients constituting the food product called emulsion, is stuffed into a casing under pressure, and further processing of the food product, such as smoking, curing and the like steps, are carried out on the encased product. The food product may also be stored and shipped encased in its casing, and, in fact is normally so handled right up to and sometimes through retail sales in the case of the large size food casings comprehended by this invention.

The designation "small food casings" refers to those casings generally employed in the preparation of small size sausage products such as frankfurters. As the name suggest, this type of food casing is small in stuffed diameter, generally within the range of from about 15 mm to less than 40 mm, and is most usually supplied as thin-walled cellulose tubes of great unit lengths. For convenience in handling, these casings, which may be 20 to 50 meters in length or even longer, are shirred and compressed to produce what is commonly referred to as "shirred casing sticks" of from about 20 cm to about 60 cm in length. Shirring machines and the products thereof are shown in U.S.

Patent Nos. 2,983,949 and 2,984,574 among others. These small size casings frequently are slit and removed from the finished product, skinless frankfurters for instance, before the product is packaged for retail sale.

"Large size food casings," by way of contradistinction, is the trade recognized designation for casings used in the preparation of the categorically larger food products, such as salami and bologna sausages, meat loaves, cooked and smoked ham butts and the like, and which are produced in sizes ranging in stuffed diameters from about as small as 40 mm to about 160 mm or even larger diameters. In general, such casings have a greater wall thickness than small size casings, and frequently are provided with a fibrous web reinforcement embedded in their walls, though they may be prepared without such supporting structure.Until fairly recent times, large size tubular casings have been supplied to the food processor mostly in flattened condition, cut to predetermined lengths of from about 0.6 m to about 2.2 m, but improvements in shirring and packaging techniques, and the increased use of automatic stuffing equipment lately has been and is increasing the demand for large size fibrous and unsupported casings in the form of shirred sticks of up to about 30 m and even longer of continuous casing.

In the preparation and use of artificial food casings, particularly small size casings formed of regenerated cellulose, the moisture content of the casings is of extreme importance. To facilitate shirring operations on these small size casings without damaging them, it is generally necessary that they be dried to a relatively low water content, usually in the range of about 11% to about 17% by weight of dry cellulose comprised in the casing, a moisture content which is relatively low compared to the moisture content of the casings comprehended by this invention. To permit ready deshirring of the compressed, shirred casing and to prevent tearing and breaking of the casing during stuffing operations, however, shirred casings having an average moisture content of between about 21% to 32% are required.This relatively narrow range of moisture content is important because excessive breakage of the casing during stuffing has been found to occur at lower moisture contents, and greater moisture content results in excessive plasticity of the casing material and consequent overstuffing.

Here it is of importance to note that the term "moisture content" as used throughout this specification and in the appended claims with reference to the cellulosic casings of the invention, is intended to refer to and should, unless otherwise specified, to be understood as referring to: the weight percent of water or moisture in the casing based in the total weight of the dry cellulose in the casing. By dry cellulose is meant the cellulose, including cellulose fibers if there are any, comprised in the casing without more than trace quantities of moisture therein contained.

A number of patents have issued in recent years dealing with the problem of the moisture content of shirred small size tubular food casings, and suggesting various methods for obtaining desired moisture levels and maintaining them during storage and shipping so that they are ready for use at the stuffing meachine. For example, in U.S.

Patent Nos. 2,181,329 to Hewitt, 3,250,629 to Turbak, and 3,471,305 to Marbach, packaging means are disclosed which will permit a multiplicity of shirred casing sticks of small size tubular casing to be humidified while packaged; and in U.S. Patent Nos.

3,222,192 to Arnold, 3,616,489 to Voo et al, 3,657,769 to Martinek, 3,809,576 to Marbach et al, and 3,981,046 to Chiu, various means are disclosed for moisturizing the small size tubular food casings before or during the shirring operation.

These references are of interest towards the full appreciation of the contribution and advance provided by this invention.

Conventionally, large size casings, which are supplied in short lengths of flattened tubing and are quite stiff in the dry state, are softened for stuffing operations by soaking in water, usually for about an hour, resulting in full moisture saturization of the casing, Because of this full saturation soaking just prior to use in stuffing operations, the need to supply such casings with any predetermined controllably added moisture content for stuffing operations has not been necessary or even advantageous. The recent wider use of automatic high speed high pressure stuffing equipment for products employing large size tubular food casings, and the consequent increased demand for such casings in shirred form as compared to the short, flattened lengths heretofore used has brought focus to bear on and emphasized the problems of moisturizing such casings by soaking just prior to use.Moreover, the need for greater control of all aspects of the manufacture and use of large size food casings has been and is increasing. For example, the uniformity of dimensions of stuffed food casings and food products processed therein has become an increasingly important commercial requirement, and casing moisture content has been found to be a factor in control of uniformity, as well as in meeting the continuing need to readily, and economically stuff the casings without damage or breakage thereof, and more importantly, to permit the stuffing of a given casing to its manufacturer's and trade designated fully stuffed size with consistent accuracy and reproducibility of results.

The importance of stuffing casings to full size will be treated in greater detail hereinafter.

Providing shirred casing sticks of small casings, having uniformly distributed throughout the length thereof the relatively narrow range of moisture content that is required for stuffing operations, has been more economically accomplished by food casing manufacturers during the manufacture and/or packaging of the casings. It has just recently become increasingly evident that similar advantages could be realized if means were developed for the casing manufacturer to supply large size casings, both in flattened and in shirred forms, which could be readily employed in casing stuffing operations, particularly the newer automated mechanical stuffing operations, without the need for pre-stuffing soaking or for other undue manual handling by the food processor.

As can be readily appreciated from the foregoing discussion, it has heretofore not been necessary or advantageous to in any way purposely control the amount of moisture content for stuffing operations in large size food casings, for the simple reason that such casings were customarily furnished in relatively easy to handle cut flattened lengths which were soaked to fully saturated condition just prior to the stuffing operation.

Thus, early experience for some time prior to the present invention yielded no evidence or offered no indication that to premoisturize the larger size casings prior to stuffing to anything less than fully saturated condition would be advantageous or desirable.

The capability of a large size food casing to be stuffed up to size is of great importance in this technology. Stuffing the casing up to size substantially eliminates emulsion breakdown, provides much enhanced control of the size and uniformity of the product, improves the dimensional stability of the product facilitating other processing steps and operations, improves size control due to performance of the stuffing operation at flatter zones in the casing pressure-stretch curves, reduces the occurrence of wrinkles and wrinkled appearance in the product, and makes for overall more efficient utilization of the casing.

The problem, thus confronting the inventor was to provide sufficient controllably added moisture in the manufactured casing so that it would not have to be soaked just prior to use in the stuffing operation, but without providing overly sufficient and unnecessary moisture content with consequent increased weight and increased packaging, handling and shipping costs. The desideratum, then, was to provide large size fibrous tubular cellulosic food casings with moisture content levels sufficiently high to afford adequate flexibility for the stuffing operation, particularly towards attainment of full stuffing size, without encountering or imposing overmosturization, increased weight, and packing, handling, storage, and transport difficulties.

With this then being the state of the art, the present invention was conceived and developed to provide a large size cellulosic tubular food product casing containing a preselected amount of moisture sufficient to the requirements of stuffing operation in which the casing is being used without the heretofore used soaking step just prior to stuffing.

The present invention also provides a large size tubular cellulosic food casing which is controllably premoisturized to a preselected condition wherein it is capable of being stuffed to its fully stuffed size at an internal pressure of from 1.3 to 4 times the internal pressure that the same casing would require to attain its fully stuffed size in a fully saturated with moisture condition.

A further significant contribution of the present invention is the provision of a large size casing with greater available casing length included in a given shirred and compressed casing stick length. This means that the frequency with which fresh shirred casing lengths are placed on the stuffing horn, with attandant lost stuffing time, is significantly reduced and much longer periods of continuous production are attained.

A still further and important advance provided by the present invention is the making available to the industry for the first time of a large size casing uniquely adapted and suited for use with newly developed automatic high speed high pressure stuffing apparatus and methods.

Amongst the numerous additional advantages and features redounding to the use of the casing according to the invention are: 1) Stuffing operation can be conducted at flatter slope zones on casing pressurestretch characteristic curves. This means that randomly occurring pressure swings around a preselected pressure set point will have less effect on finished product size by comparison with the effect of such swings on a similar casing fully soaked and having a relatively steeper slope to its pressurestretch characteristic curve.

2) Casings according to the present invention are much less affected by casing manufacturing parameter (other than moisture) variations and aberrations.

3) The use of the casings of this invention obviates the problem of degradation of casing treatments through oversoaking.

4) The loss of casing material is avoided, such loss as occurs for instance when soaked casing is left over at the end of the operating period or on shutdown of a stuffing run for any reason.

5) The feature mentioned hereinabove, that the invention permits the use of longer shirred lengths of casing, makes for added advantages, efficiencies, economies in the packaging, handling, storage, transport and utilization of the casings.

6) The invention eliminates the cost and control problems, temperature for instance, attending the soaking of casings at the stuffing machine just prior to use.

7) The elimination of soak tanks is in itself a great advantage, since such tanks are a potential health hazard. Glycerine frequently included in the casings leaches out in the course of prolonged soaking, resulting ultimately in mold and bacteria incidence. Other contamination risks also attend the use of soak tanks at stuffing machine locations.

According to the present invention there is provided a cellulosic tubular food product casing comprising a fibrous web embedded in the wall thereof, said casing: (a) being such that when fully stuffed it has a diameter of from 40 mm to 200 mm; (b) a moisture content (as hereinbefore defined) of not less than 25% to 71% moisture; and (c) being capable of being stuffed to its fully stuffed size at an internal pressure of from 1.3 to 4 times the internal pressure that the same casing would require to attain its fully stuffed size if fully saturated with moisture.

A preferred embodiment of the invention comprises a casing wherein the moisture content is about 35% of the cellulose comprised in the casing, and which is capable of being stuffed to its fully stuffed size at an internal pressure of from 2 to 3 times the internal pressure that the same casing would require to attain its fully stuffed size if fully saturated with moisture.

Useful and advantageous embodiments of the present invention include shirred lengths as well as flattened cut lengths of casing.

In accordance with the present invention there are provided large size fibrous, tubular, cellulosic food casings having sufficient moisture content to permit said food casings to be readily stuffed with a food emulsion, and to be within a moisturization range such that they may be fully stuffed at from 1.3 to 4 times the internal pressure that would be required to stuff the same casing if it was fully saturated with moisture instead of controllably saturated to a lesser degree. Preferably, the tubular casings will have a moisture content of from 29% to 42% of dry cellulose in the casing and an internal pressure capability of 2 to 3 times that which they would have if fully saturated.It has been discovered that large size tubular cellulosic casings, including tubular fibrous casings, having the moisture content herein described, are completely suitable for stuffing with the newer types of automatic high speed, high pressure mechanical stuffing apparatus without further moisturization by the food processor at the stuffing point, and such casing can be readily shipped, and handled without difficulty and with considerable advantages in the meat processing arts.

Accordingly, the present invention also provides a method of making a food product, which comprises stuffing a cellulosic tubular food product casing of the present invention with a food emulsion and without the addition of further moisture prior to the stuffing.

The fibrous, tubular food casings in accordance with the present invention may be prepared by a method which comprises imbuing a large size cellulosic food casing with a controlled quantity of water sufficient to permit said food casing to be stuffed with food emulsion.

The amount of water, as mentioned hereinabove, is in the range of from 25% to 71% of the weight of dry cellulose comprised in the casing.

Large size tubular cellulosic food casings suitable for use as casings according to the present invention may be prepared by any one of the methods well known in the art.

The tubular casings are generally flexible tubing formed of regenerated cellulose, cellulose ethers and the like, and can be prepared by known processes, such as the cuprammonium, deacetylation of cellulose acetate, denitration of cellulose nitrate processes, and preferably the viscose process. Tubular casings reinforced with fibers such as, for example, rice paper and the like, hemp, rayon, flax, sisal, nylon, polyethylene terephthalate and the like, are most advantageously employed in applications requiring large diameter tubular food casings where strength is important. Tubular fibrous casings can be made by methods and apparatus described, for example, in U.S.Patent Nos. 2,105,273; 2,144,899; ' 2,910,380; 3,135,613; and 3,433,663 As is well known in the art, tubular cellulosic casings prepared by any one of the above mentioned well known methods are customarily treated with glycerine as a humectant and softening or plasticizing agent to provide resistance to drying or cracking of the casing prior to stuffing. The glycerine treatment is usually carried out by passing the casing while still in its gel state through an aqueous glycerine solution, after which the plasticized casing is dried to a predetermined moisture content prior to further processing or winding up on reels for storage. Generally, large size tubular casings will contain 25% to 40% glycerine based on the weight of dry cellulose in the casing and have a residual moisture content of about 7% to 15%.

Large size tubular cellulosic food casings according to the invention require an average moisture content of at least 25% and preferably 35%, to impart the desired flexibility for stuffing.

The moisture content upper limit does not exceed 71% of the dry cellulose in the casing. Initially, in the development of the invention, it was thought that no criticality attached to the upper limit of moisture content, except of course for the economic considerations of handling, packaging, transporting, and storing excess water which added nothing to the invention.

The rationale that excess water would do no harm, other than economic, was doubtlessly prompted by the experience with the known stuffing operations where the cut casing lengths were soaked to full saturation prior to being stuffed. It became apparent in the course of experimental and development work however, that, just as is the case with small casings, too much moisture in the large casings causes adverse effects in the stuffing operation, most particularly in the newer automatic high speed pressure stuffing techniques.

Excessive moisture, above say the 35% figure herein noted, lowers the casing internal pressure resistance capability.

While this made for no descernible disadvantage in using the casings in the older known, relatively slow, low pressure stuffing techniques, the use of such overmoisturized casing in some of the newer stuffing modes resulted in poorer sizing control of the product, and, in some instances, irregularities in the product diameter, casing distortion and/or rupture.

It also became apparent that while additional strength factors in large casings might not be of great importance in the known more conventional methods of stuffing, they would be, and indeed are, of critical significance in automatic high speed high pressure stuffing operations. In stuffing the conventional cut lengths of large size casings, the casing is soaked fully to saturation, placed on a stuffing horn, held or restrained, filled, tied off, and removed from the stuffing apparatus. The hold or restraining of the casing at the stuffing horn outlet effects holdback and permits the casing length being filled to attain its preselected diameter.At relatively low stuffing pressures, holdback is easily effected, but in the more modern stuffing operations with premoisturizing casing according to this invention, holdback force must needs be greatly increased to effect proper product sizing. As a consequence, the casings must be stronger and especially able to withstand higher internal pressures.

By controlling the upper limit of moisture content in the casing to not more than about 71%, preferably about 35%, according to this invention, it has been found that the internal pressure reaction capability of the casing increases to as much as 4 times the internal pressure reaction capability to attain fully stuffed diameter with the same casing when it is fully saturated with moisture.

A typically illustrative holdback technique used in modern automatic high speed high pressure large casing stuffing operations is treated in United States Patent Nos. 4,077,090 and 4,164,057.

Tubular cellulosic food casings of the present invention may be prepared by applying the requisite preselected quantities of water to suitable dried tubular food casings, using any of a number of moisturizing methods known in the art.

Casings may be moisturized according to the present invention by spraying, brushing, dipping, slugging, and other known efficacious techniques. The casing may be treated with the desired amounts of moisture as flattened casing either on or off storage reels, or as it is being advanced through a shirring machine. By proportioning the amount of water to the size of casing to be treated, resonably precise control of the moisture content of the casings of the invention may be attained.

In preparing the tubular cellulosic food casings of the present invention, various other materials or treatments well known in the art can be utilized to impart particular characteristics or properties to the casings provided, of course, that such material or treatment is compatible with and has no adverse effect on the food casings or the use thereof. In copending British Patent Application No. 19922/77 (Serial No.

1584435) controllably moisturized casings according to this invention are modified by the inclusion therein of antimycotic agents to prevent mold and fungi growth. Among further treatments which may be employed are, by way of illustration, coatings applied to improve peelability of the casings from encased food products such as disclosed in U.S. Patent No. 2,901,358 to Underwood; coatings applied for improving adhesion to dry sausage products such as disclosed in U.S. Patent No. 3,378,379 to Shiner et al; coatings applied to afford vapor and/or barrier properties such as disclosed in U.S.

Patent No. 3,886,979 to Rasmussen, and the like. Moreover, tubular casings of the present invention may be shirred and compressed employing conventional shirring machines and methods as disclosed, for example, in U.S. Patent Nos. 2,984,574 to Matecki, 3,110,058 to Marbach, and 3,397,069 to Urbutis et al.

The present invention will now be further described by means of the following Examples and the accompanying drawing.

The drawing is a graph on Cartesian coordinates showing a family of stretch pressure curves for the fibrous casing of Example III.

Example I A quantity of tubular fibrous casing, trade designation Size 8 Regular Clear Fibrous, was made up into ten shirred sticks for each moisture level, each 15.2 meters in unshirred casing length, to be moisturized to target moisture levels of 23%, 29%, 33%, 44% and 57% moisture content. The actual moisture contents attained were, respectively, 25.1%, 30.4%, 32.6%, 44.9% and 56.0%.

Five samples were stuffed from each stick on an automatic stuffing machine to a stuffed product length of I meter at a stuffing speed of 30 centimeters per second with bologna emulsion.

Stuffed diameters of each sample produced were measured at both ends and in the middle, both before and after processing. The acceptable variation from the recommended stuffed diameters used in this example is +.03 inches. Casing moisture levels were rechecked at the time of stuffing.

The results of these stuffing test runs are presented below in Tables 1 to 5.

The data from the Tables 1 to 5 show that consistently reproducible results are obtained over moisture content ranges of casings according to the invention. Stuffing machine adjustments were made to accommodate sample moisture level differences, and the casings were found to adapt to these machine adjustments as well as to normally encountered operational aberrations. The machine settings indicated as effecting high, very high, intermediate, and low casing holdback, were attained by varying the distance between sizing discs and snubbing rings on the machine, by using different diameter sizing discs, and by combinations of these.

Similar casing samples, fully soaked and stuffed on the same apparatus, have been found to yield inferior performance.

TABLE 1 Size 8 Regular Clear Fibrous 57% Nominal Moisture Level Recommended Stuffed.

Diameter 4.79 Diameter Measurements, Inches Sample "A"-9 Shirred Sticks, 5 Pcs. Stuffed per Stick Total 45 Samples Stuffed (40" Lg.): Machine set for high casing holdback.

Ist. Tie Mid. 2nd. Tie Total Mean Dia. M 4.80 4.80 4.78 4.79 Std. Dev. a 0.01 0.01 0.02 0.02 Sample "B"-Total Sample 5 Pcs.: Machine set for high casing holdback.

Mean Dia. M 4.77 4.79 4.77 4.7.8 Std.Dev a 0.01 0.02 0.02 0.02 Sample "C"--Total Sample 3 Pcs.: Machine set for low casing holdback.

Mean Dia. y 4.63 4.65 4.66 4.65 Std. Dev. a 0.02 0.01 0.01 0.02 TABLE 2 Size 8 Regular Clear Fibrous 44% Nominal Moisture Level Recommeded Stuffed Diameter 4.79 Diameter Measurements, Inches Sample "A"-8 Shirred Sticks, 5Pcs. Stuffed per Stick Total 40 Samples Stuffed (40" Lg.): Machine set for high casing holdback.

Ist. Tie Mid. 2nd. Tie Total Mean Dia. 1 4.80 4.80 4.79 4.80 Std. Dev. a 0.02 0.02 0.02 0.02 Sample "B"-Total Sample 5 Pcs.: Machine set for high casing holdback.

Mean Dia. y 4.76 4.77 4.76 4.76 Std. Dev. a 0.01 0.01 0.01 0.01 Sample "C"-Total Sample 3 Pcs.: Machines set for low casing holdback.

Mean Dia. y 4.65 4.68 4.68 4.67 Std. Dev. a 0.01 0.00 0.00 0.02 TABLE 3 Size 8 Regular Clear Fibrous 33% Nominal Moisture Level Recommended Stuffed Diameter 4.79 Diameter Measurements, Inches Sample "A"-9 Shirred Sticks, 5 Pcs. Stuffed per Stick Total 45 Samples Stuffed (40" Lg.): Machine set for high casing holdback.

Ist. Tie Mid. 2nd. Tie Total Mean Dia. 4.80 4.81 4.80 4.81 Std. Dev. a 0.02 0.02 0.02 0.02 Sample "B"-Total Sample 5 Pcs.: Machine set for very high casing holdback.

Mean Dia. y 4.85 4.85 4.84 4.85 Std. Dev. a 0.00 0.01 0.01 0.01 Sample "C"-Total Sample 3 Pcs.: Machine set for intermediate casing holdback.

Mean Dia. y 4.73 4.75 4.73 4.74 Std. Dev. a 0.01 0.01 0.01 0.01 TABLE 4 Size 8 Regular Clear Fibrous 29% Nominal Moisture Level Recommended Stuffed Diameter 4.79 Diameter Measurement, Inches Sample "A"-9 Shirred Sticks, 5 Pcs. Stuffed per Stick Total 45 Samples Stuffed (40" Lg.): Machine set for high casing holdback.

Ist. Tie Mid. 2nd. Tie Total Mean Dia. u 4.78 4.78 4.77 4.78 Std. Dev. a 0.01 0.01 0.01 0.01 Sample "B"-Total Sample 5 Pcs.: Machine set for high casing holdback Mean Dia. y 4.77 4.78 4.77 4.77 Std. Dev. a 0.01 0.00 0.00 0.01 Sample "C"-Total Sample 5 Pcs.: Machine set for intermediate casing holdback.

Mean Dia. Ci 4.72 4.73 4.72 4.72 Std. Dev. a 0.01 0.01 0.01 0.01 TABLE 5 Size 8 Regular Clear Fibrous 23% Nominal Moisture Level Recommended Stuffed Diameter 4.79 Diameter Measurements, Inches Sample "A"-2 Shirred Sticks, 5 Pcs. Stuffed per Stick Total 10 samples Stuffed (40" Lg.): Machine set for very high casing holdback.

Ist. Tie Mid. 2nd. Tie Total.

Mean Dia. ,u 4.78 4.78 4.77 4.78 Std. Dev. a 0.04 0.02 0.02 0.03 Sample "B"-Total Sample 5 Pcs.: Machine set for high casing holdback.

Mean Dia. L 4.71 4.73 4.71 4.72 Std. Dev. a 0.01 0.01 0.00 0.01 Example II Stuffing tests were run on different trade-used fibrous casings with moisture contents from about 21% up to about 81% of the total casing weight with the following results: a.) 21.3% moisture; 6S casing; 2 sticks; split both casings trying to get casings over sizing disc.

b.) 26.1% moisture; 6-1/2K casing; 2 sticks; made 30 pieces of 40 inch stuffed product; casing periodically broke and sometimes blew closure clip off end during stuffing. Had to double clip some ends to finish test.

c.) 37.9% moisture; 8M casing; 2 sticks; made 30 pieces of 40 inch product without problems.

d.) 43.3% moisture 6-1/2K casing; 2 sticks; made 34 pieces of 40 inch product without problems.

e.) 43.3% moisture; 6-1/2KM casing; 2 sticks; made 30 pieces of 40 inch product without problems.

f.) 50.1% moisture; 7 1/2K casing; 1 stick; made 15 pieces of 40 inch product without problems.

g.) 56.8% moisture; 6S casing; 2 sticks; made 40 pieces of product without problems.

h.) 59.3% moisture; 6 1/2KM casing; 2 sticks; made 31 pieces of product without problems.

i.) 61.8% moisture; 6 1/2K casing; 2 sticks; made 26 pieces of product without problems.

j.) 62.1% moisture; 8M casing; 2 sticks; made 31 pieces of product without problems.

k.) 72.0% moisture; 8M casing; 2 sticks made 30 pieces of product without problems.

1.) 73% moisture; 6S casing; 2 sticks; made 18 pieces of product without problems.

m) 76.9% moisture: 6 1/2K casing; 2 sticks; made 20 pieces of product without problems.

n.) 80.6% moisture; 7 1/2K casing; 2 sticks; made 32 pieces of product without problems.

These tests also indicated that little or no advantage in maintaining sizing and stuffing speed control accrued with moisture contents of from about 35% on upwards, and that at moisture contents above 71%, the excess water tended to interfere with other desirable and necessary ingredients of the casing, as well as adding unnecessary weight and bulk to the casings. These tests also clearly indicated that the practical lower limit for controllably moisturized casings according to the invention was 25% moisture content.

Fully saturated casings tested on the same stuffing apparatus again yielded inferior results.

Example III A quantity of tubular fibrous casing, trade designation Size 8 Regular Clear Fibrous, was made up into shirred sticks for each moisture level examined, and tested experimentally to determine the stretch pressure relationship of casings according to the invention at different moisture contents and as compared with casing of the same type fully saturated with moisture.

The accompanying drawing is a graph on Cartesian coordinates showing a family of curves expressing the stretch-pressure relationships of the casing tested at moisture contents of fully saturated, 66.5%, 36.6%, and 28.8%. Inspection of the drawing shows that the recommended fully stuffed diameter of the tested casing is 4.79 inches, as indicated by the horizontal line drawn through that value on the graph. It is seen further, that to attain the recommended stuffed diameter with 28.8% moisturized casing, a pressure of 465 mm of mercury is required; with 36.6% moisturized casing, a pressure of 388 mm of mercury is required; and with 66.5% moisturized casing, a pressure of 328 mm of mercury is required, while to attain the same recommended stuffed diameter with the same casing fully soaked, a pressure of only 185 mm of mercury is required.This example thus shows an internal pressure requirement reaction capability to attainment of fully stuffed size for controllably moisturized casings according to the invention of from about 1.8 to about 2.5 times the internal pressure reaction to the attainment of fully stuffed size with the same casing fully saturated with moisture ratios within the ranges shown by experience and by other experiments to be practical and attainable in practicing the invention.

The curves of the drawing also illustrate that at the normal set point, that is to say at whatever pressure is needed to maintain the recommended stuffed diameter of 4.79 inches, the curves representing the controllably premoisturized casings according to the invention have flatter or less steep slopes than the curve representing the fully soaked casing. Thus, for any encountered increment or decrement in pressure during stuffing operations, the departure from recommended stuffed diameter with the controllably remoisturized casings will be significantly iess than it would be with the fully soaked casing. Casings according to the invention therefore make the maintenance of recommended stuffed diameter more attainable.

Casings according to the invention have shown consistently reproducible and good results in closely monitored field tests. The benefits and advantages of the invention will undoubtedly be recognized and appreciated by the industry.

A particular benefit noted with shirred casing premoistured according to the invention is that the elimination of the soaking just prior to stuffing step, obviates the problem of casing stick growth from over-moisturization in a soak tank. Stick growth or expansion caused by full saturation soaking at the stuffing machine site can and does make the casing sticks too long for mounting properly on the stuffing horn. This is an important attribute of the invention.

In the light of the foregoing description, there will undoubtedly occur to persons conversant with the art, numerous alternative and combination modes of practicing this invention. It is possible, and indeed anticipated, that the invention will be combined with various and sundry types of casings having other features and attributes not incompatible with controlled premoisturization, such as for instance, casings enclosed in elastic outer wrappers, casings provided with gas and/or moisture barrier coatings, casings with additives to improve peelability from an encased product, casings with additives to improve adhesion of the casing to an encased product, and other types and forms, all of which, while not described herein in detail as to themselves, are within the scope of this invention to the extent that they are combined therewith and/or incorporated therein.It is of course also contemplated that casings according to the invention may be formulated in combination with shrink film overwraps.

WHAT WE CLAIM IS: 1. A cellulosic tubular food product casing comprising a fibrous web embedded in the wall thereof, said casing: (a) being such that when fully stuffed it has a diameter of from 40 mm to 200 mm; (b) having a moisture content (as hereinbefore defined) of from 25% to 71% by weight of dry cellulose comprised in the casing; and (c) being capable of being stuffed to its fully stuffed size at an internal pressure of from 1.3 to 4 times the internal pressure that the same casing would require to attain its fully stuffed size if fully saturated with moisture.

2. A casing as claimed in claim 1 wherein the moisture content is from 29% to 42%, and said internal pressure reaction to attainment of fully stuffed size is from 2 to 3 times the internal pressure reaction to attainment of fully stuffed size with said casing fully saturated with moisture.

3. A casing as claimed in claim 1 or claim 2 including a fluid barrier coating.

4. A casing as claimed in any one of claims 1 to 3 including a coating to improve peelability of the casing from an encased product.

5. A casing as claimed in any one of claims 1 to 4 including a coating to improve adhesion of the casing to an encased product.

6. A casing as claimed in any one of claims 1 to 5 shortened to a length shorter than its original length.

7. A casing as claimed in claim 6 shirred and compressed to a length shorter than its original length.

8. A casing as claimed in claim 6 radially wound into a configuration having a length shorter than the casing original length.

9. A casing as claimed in claim 6, 7 or 8 encased in an elastic fitted outer wrapping.

10. A casing as claimed in claim 6, 7 or 8 encased in a shrink fitted outer wrapping.

11. A cellulosic tubular food product casing, as claimed in claim 1 and substantially as herinbefore described with reference to any one of the foregoing Examples.

12. A cellulosic tubular food product casing substantially as hereinbefore described with reference to the accompanying drawing.

13. A method of making a food product, which comprises stuffing a cellulosic tubular food product casing, as claimed in any of claims 1 to 12, with a food emulsion and without the addition of further moisture prior to the stuffing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. there will undoubtedly occur to persons conversant with the art, numerous alternative and combination modes of practicing this invention. It is possible, and indeed anticipated, that the invention will be combined with various and sundry types of casings having other features and attributes not incompatible with controlled premoisturization, such as for instance, casings enclosed in elastic outer wrappers, casings provided with gas and/or moisture barrier coatings, casings with additives to improve peelability from an encased product, casings with additives to improve adhesion of the casing to an encased product, and other types and forms, all of which, while not described herein in detail as to themselves, are within the scope of this invention to the extent that they are combined therewith and/or incorporated therein. It is of course also contemplated that casings according to the invention may be formulated in combination with shrink film overwraps. WHAT WE CLAIM IS:

1. A cellulosic tubular food product casing comprising a fibrous web embedded in the wall thereof, said casing: (a) being such that when fully stuffed it has a diameter of from 40 mm to 200 mm; (b) having a moisture content (as hereinbefore defined) of from 25% to 71% by weight of dry cellulose comprised in the casing; and (c) being capable of being stuffed to its fully stuffed size at an internal pressure of from 1.3 to 4 times the internal pressure that the same casing would require to attain its fully stuffed size if fully saturated with moisture.

2. A casing as claimed in claim 1 wherein the moisture content is from 29% to 42%, and said internal pressure reaction to attainment of fully stuffed size is from 2 to 3 times the internal pressure reaction to attainment of fully stuffed size with said casing fully saturated with moisture.

3. A casing as claimed in claim 1 or claim 2 including a fluid barrier coating.

4. A casing as claimed in any one of claims 1 to 3 including a coating to improve peelability of the casing from an encased product.

5. A casing as claimed in any one of claims 1 to 4 including a coating to improve adhesion of the casing to an encased product.

6. A casing as claimed in any one of claims 1 to 5 shortened to a length shorter than its original length.

7. A casing as claimed in claim 6 shirred and compressed to a length shorter than its original length.

8. A casing as claimed in claim 6 radially wound into a configuration having a length shorter than the casing original length.

9. A casing as claimed in claim 6, 7 or 8 encased in an elastic fitted outer wrapping.

10. A casing as claimed in claim 6, 7 or 8 encased in a shrink fitted outer wrapping.

11. A cellulosic tubular food product casing, as claimed in claim 1 and substantially as herinbefore described with reference to any one of the foregoing Examples.

12. A cellulosic tubular food product casing substantially as hereinbefore described with reference to the accompanying drawing.

13. A method of making a food product, which comprises stuffing a cellulosic tubular food product casing, as claimed in any of claims 1 to 12, with a food emulsion and without the addition of further moisture prior to the stuffing.