WO2008106566A1

WO2008106566A1 - Use of hydrocolloid coating solutions in food products

Info

Publication number: WO2008106566A1
Application number: PCT/US2008/055202
Authority: WO
Inventors: Michael J. Bonner
Original assignee: The Arnhem Group
Priority date: 2007-02-28
Filing date: 2008-02-27
Publication date: 2008-09-04

Abstract

The present invention relates to the application of at least one liquid hydrocolloid solution to the surface of a food product, such as meat, poultry, or fish, to inhibit the growth of bacteria, and in particular Listeria monocytogenes. The at least one liquid hydrocolloid may also reduce purge loss of natural juices and prevent color deterioration.

Description

USE OF HYDROCOLLOID COATING SOLUTIONS IN FOOD PRODUCTS

FIELD OF THE INVENTION

[001] The present invention relates to the unexpected discovery of the use of a liquid hydrocolloid protein solution for application to the surface of foods, including meat, poultry, and fish, to inhibit the growth of bacteria, and in particular Listeria monocytogenes, as well as to reduce purge loss of natural juices, to prevent color deterioration, and other benefits.

BACKGROUND OF THE INVENTION

[002] Encapsulation and coatings are used to protect many food ingredients, such as flavor oils, oleoresins, spices, chemicals, vitamins, and colorants, in food processing operations from conditions like heat, moisture, and acidity that cause them to degrade. Thus, the flavors resulting from those core ingredients exhibit increased shelf life in the food product and better delivery when the product is consumed.

[003] Spices, oleoresins, flavor oils, colorants, and other chemicals are typically added during food processing to produce the desired flavors, taste, and appearance. The oleoresins and flavor oils are typically coated on carriers, such as salt and dextrose, and mixed with other dry food ingredients before they are used for food production. Because of the exposure of those additives to conditions such as moisture, light, and oxygen, the carrier coated oleoresin and flavor oils are susceptible to oxidation and often lose their desired flavor value very quickly.

[004] The encapsulation technologies generally employed for the protection of those ingredients include coating, spray drying, extrusion, and coacervation. Other examples include co-extrusion processes, which utilize regenerated native collagen

i dough as a casing material for the likes of comminuted sausage meats. Finished encapsulation products are normally in the solid form and can be of different mesh sizes.

[005] U.S. Patent No. 5,690,990 discloses a process for encapsulating flavor oils, oleoresins, and spices in a colloid gel, and is incorporated herein in its entirety. The method is disclosed as typically practiced by first forming a colloid gel through dissolving a selected gelatin in water until the mixture turns into a very viscous gel. Oleoresin or flavor oil is added while the gel is being mixed and mixing is continued until the core materials are thoroughly dispersed uniformly throughout the gel matrix. In some situations, the colloid gel is disclosed as needing two or more gelling polymers to obtain the desired properties of the gel matrix. Due to the character of the gel matrix and the hydrophobic and hydrophilic nature of the oleoresin and gel polymers, the oleoresin or flavor oil stays in the gel matrix with reasonable stability. The reference discloses that the gel matrix may be used in the gel form and injected or otherwise mixed into meat products, and also may be used directly in the food system or further processed and then incorporated in the food system.

[006] Besides protecting many of the core ingredients of food from food processing operations conditions such as heat, moisture, and acidity, it is also increasingly important to protect foods, such as meats, poultry, and fish, from the growth of bacteria. Bacterial growth is one of the primary causes of meat spoilage and may result in unpleasant odors, change in color, the formation of slime, the release of toxins, and off flavors. The growth of bacteria may also result in sickness or even death to the consumer once the food is ingested. [007] The growth of bacteria is a particular problem in the storage of primal and sub-primal meat cuts, ready-to-eat meats, and case-ready-meats. The use of vacuum packaging does not prevent this growth.

[008] Listeria monocytogenes is a particular strain of bacteria that has been found to be troublesome in the storage of foods such as meats, poultry and fish. Listeria monocytogenes has been associated with such foods as fermented raw-meat sausages, raw and cooked poultry, raw meats (all types), and raw and smoked fish. Its ability to grow at temperatures as low as 3°C permits multiplication in refrigerated foods.

[009] Heretofore, there have been no known food technologies available for the simple and economic encapsulation of foods such as meat, poultry, and fish substrates to not only protect many of the core food ingredients from degradation, but to also both inhibit the growth of bacteria, including Listeria monocytogenes, and to achieve other benefits such as the reduction of juice loss ("juice purge") and the prevention of color deterioration. The current inventors have surprisingly and unexpectedly found that the growth of bacteria on food may be inhibited by the application of a liquid hydrocolloid solution. That discovery may be significant, in part, since the at least one liquid hydrocolloid solution is, in general, cheaper and/or easier to make than other substances with the same or similar bacteria control, biocontrol, or bioprotective effect.

[010] It is therefore an object of the present invention to provide for the use of a liquid colloid solution that can be applied to the surface area of foods, such as whole or sliced meats, poultry, and fish, to inhibit the growth of bacteria, such as Listeria monocytogenes. It is also an object of the present invention to provide for the use of a liquid colloid solution to reduce natural juice losses and to help prevent color deterioration, possibly in combination with the inhibition in the growth of bacteria.

SUMMARY OF THE INVENTION

[011] Disclosed herein is a method of inhibiting the growth of bacteria on foods, such as meat, poultry, or fish, comprising applying to the surface of the food a coating comprising a liquid hydrocolloid solution. In one embodiment, the coating may be considered a "bioprotective" coating due to its beneficial effects versus bacteria.

[012] The liquid hydrocolloid solution comprises at least one polymer capable of forming a stable polymer gelatin. Suitable polymers include, but are not limited to, animal proteins, plant polysaccharides, animal glues, collagen, whey, casein, starches, gums, and hydrolysates. In one embodiment, the at least one polymer is an animal protein. In another embodiment, the at least one polymer is a hydrolysate. In a further embodiment, the at least one polymer is a starch.

[013] The liquid hydrocolloid solution may further comprise at least one core food processing ingredient that may heretofore be known to the skilled artisan or later discovered. Suitable core food processing ingredients include, but are not limited to, flavor oils, oleoresins, spices, vitamins, and colorants. In one embodiment, the at least one core food processing ingredient is a flavor oil. In another embodiment, the at least one core food processing ingredient is a vitamin. In a further embodiment, the at least one core food processing ingredient is a colorant. [014] The food may be selected from any solid foodstuff on which it is desirous to prevent the growth of bacteria and/or to achieve any other benefits described in this application. The food may be referred to herein as a "substrate" or "food substrate." In one embodiment, the food is meat. Suitable meats may be selected from, but are not limited to, beef, pork, lamb, bison, and venison. In another embodiment, the food is fish. Suitable fishes may include, but are not limited to, sole, catfish, flounder, salmon, tuna, cod, snapper, trout, whiting, red snapper, grouper, mahi mahi, and bass. In a further embodiment, the food is poultry. Suitable poultry include, but are not limited to, chicken, turkey, duck, goose, and ostrich. In yet another embodiment, the food is a primal cut. In still a further embodiment, the food is a non-primal cut.

[015] The food may be prepared in most any product form. In one embodiment, the food substrate is a ready-to-eat food product. Ready-to-eat food products may include, for example, hot dogs, luncheon meats, cold cuts, fermented and dry sausages, and deli-style food products. In another embodiment, the food is a case-ready food product. In a further embodiment, the food is a fresh-cut food product. In yet another embodiment, the food substrate is a sliced product. In yet a further embodiment, the food substrate is packaged in vacuum-sealed packaging.

[016] The method of inhibiting the growth of bacteria described herein may further comprise applying to the surface of a food at least one biocontrol agent.

[017] The bacteria whose growth is inhibited by the method described herein may be any bacteria whose growth is inhibited by the application of the at least one liquid hydrocolloid solution to the food. Inhibition of growth, as used herein, means that the bacteria experiences less growth in the presence of the at least one liquid hydrocolloid solution than not in the presence of the at least one liquid hydrocolloid solution, when evaluated under the same or similar conditions. In one embodiment, the bacteria is Listeria monocytogenes. In another embodiment, the bacteria is E. coli. In a further embodiment, the bacteria is Salmonella.

[018] Still further disclosed is a method of inhibiting the growth of bacteria on a food substrate, comprising applying to the surface of the food substrate a coating comprising a liquid hydrocolloid solution, and wherein the food substrate also exhibits at least one of a decrease in natural juice loss and a decrease in color deterioration, as compared to a food substrate under the same or similar conditions to whose surface the at least one liquid hydrocolloid solution has not been applied.

BRIEF DESCRIPTION OF THE FIGURES

[019] Figure 1 is a graph illustrating the effects of a liquid hydrocolloid solution coating according to the present invention, either alone or in combination with a high concentration biocontrol agent, on the inhibition of the growth of Listeria monocytogenes on irradiated ham meat slices during refrigerated storage at 4⁰C.

[020] Figure 2 is a graph illustrating the effects of a liquid hydrocolloid solution coating according to the present invention, either alone or in combination a low concentration biocontrol agent, on the inhibition of the growth of Listeria monocytogenes on irradiated ham meat slices during refrigerated storage at 4⁰C.

[021] Figure 3 is a graph illustrating the effects of a liquid hydrocolloid solution coating according to the present invention, either alone or in combination with a low concentration biocontrol agent, on the inhibition of the growth of Listeria monocytogenes on turkey slices during refrigerated storage at 4⁰C.

[022] Figure 4 is a graph illustrating the effect of a liquid hydrocolloid solution coating according to the present invention on the prevention of natural juice purge in a beef loin sample.

[023] Figure 5 is a graph illustrating the effect of a liquid hydrocolloid solution coating according to the present invention on the prevention of color deterioration in a beef loin sample.

[024] Figure 6 is a graph illustrating the effect of a liquid hydrocolloid solution coating according to the present invention on the prevention of redness color deterioration in a beef loin sample.

[025] Figure 7 is a graph illustrating the effect of a liquid hydrocolloid solution coating according to the present invention on the prevention of color deterioration in a beef loin sample.

DETAILED DESCRIPTION OF THE INVENTION

[026] It is one object of the present invention to provide for the surprising and unexpected use of a liquid hydrocolloid solution that can be applied to the surface area of food, such as whole or sliced meats, poultry, and fish, to inhibit the growth of bacteria, in particular Listeria monocytogenes. It is another object of the present invention to provide for the use of a liquid hydrocolloid solution that can be applied to the surface area of food, such as whole or sliced meats, poultry, and fish, to reduce natural juice losses and/or to help prevent color deterioration. It is a further object of the present invention to provide for the use of a liquid hydrocolloid solution that can be applied to the surface area of food, such as whole or sliced meats, poultry, and fish, for at least one purpose chosen from the inhibition of bacteria, the reduction of natural juice losses, and the prevention of color deterioration.

[027] The at least one liquid hydrocolloid solution comprises water and at least one colloid. In one embodiment, the at least one colloid comprises at least one polymer. In another embodiment, the at least one colloid is a gelatin. In a further embodiment, the at least one colloid comprises a gelatin matrix of at least one polymer. In such an embodiment, the matrix may further comprise at least one core food processing ingredient. Core food processing ingredients may be selected from, for example: oleoresins of spices or vegetables, such as paprika, bay leaves, garlic, onion, black pepper, capsicum, ginger, basil, mace, rosemary, celery, thyme, nutmeg, anise, and sage; oil flavors, such as pimento, cardamom, cassia, garlic, black pepper, fennel, clove, dillweed, sage, clove leaves, lemon oil, nutmeg, cinnamon, winter green, peppermint, and bay; and, synthetic and/or natural flavorings, such as vanilla, lemon oil, orange oil, grapefruit, lime, apple, pear, peach, strawberry, and cherry. The above oleoresins, oil flavors, and synthetic and/or natural flavors may be used individually or in a mixture as is well known in the art.

[028] The at least one polymer may be selected from animal protein polymers, plant polysaccharides, animal glues, collagen, whey, casein, starches, gums, hydrolysates, and other polymers that can form a stable polymer gelatin. In one embodiment, the at least one polymer is an animal protein polymer. In another embodiment, the at least one polymer is a bovine protein polymer. In an embodiment wherein the at least one colloid comprises a gelatin matrix of at least one polymer, at least one second polymer different from the at least one polymer may be used. In such embodiments, the at least one second polymer different from the at least one polymer may effect at least one of an improvement in the matrix's viscoelastic properties, an improvement in the matrix's physical properties, an improvement in the matrix's chemical properties, and more complete encapsulation of any at least one core food processing ingredient. In another embodiment wherein the at least one colloid comprises a gelatin matrix of at least one polymer, the composition of the at least one colloid is selected such that the gelatin matrix remains stable under specific temperature, concentration, and processing conditions. In a further embodiment wherein the at least one colloid comprises a gelatin matrix of at least one polymer, the at least one polymer is an animal protein. In yet another embodiment, the at least one colloid is chosen from FLAVEX 35, FLAVEX 75, FLAVEX 90, FLAVEX 95, FLAVEX 201 , FLAVEX PLUS, and CUREGEL 150, hydrocolloid proteins manufactured by FLAVEX Technologies, a division of The Arnhem Group.

[029] The at least one colloid comprising a gelatin matrix of at least one polymer may encapsulate any of at least one core food processing ingredient. In order to encapsulate the at least one core food processing ingredient with the at least one polymer, the colloid polymer gelatin may be mixed with the at least one core food processing ingredient under high shear pressure to create a stable colloid gel matrix with the encapsulated core ingredients. Without wishing to be bound by theory, it is believed that the core ingredients may be encapsulated in the colloid gel matrix through the interactions of their hydrophobic and hydrophilic properties. Encapsulation may assist in maintaining a separation between the at least one core food processing ingredient and air and/or other components present in the food system, thereby reducing the opportunity for oxidation, degradation, or other chemical reaction of those core ingredients. In one embodiment, the at least one colloid comprising a gelatin matrix of at least one polymer is selected such that, even if heat processing temperatures are used to convert the colloid gelatin matrix into a liquid, the at least one core food processing ingredient will remain encapsulated by the at least one polymer.

[030] The liquid hydrocolloid solution of the present invention may be formed by mixing the at least one colloid in water at an appropriate temperature to dissolve it therein. The mixing may be accomplished by any mechanical action mixer now known to the skilled artisan or hereafter discovered. In one embodiment, the at least one polymer is mixed with a sufficient quantity of water such that the at least one polymer is substantially dissolved therein. In another embodiment, the at least one colloid comprising a gelatin matrix of at least one polymer is mixed with a sufficient quantity of water such that the gelatin matrix is substantially dissolved therein. In one embodiment, the temperature of the water is between about 90° F and about 160° F. In another embodiment, the temperature of the water is about 90° F. In a further embodiment, the temperature of the water is determined by the gelling temperature of the selected gelatin and/or other polymers to be dissolved therein. In yet another embodiment, a lightening mixture may also be mixed with the at least one liquid hydrocolloid solution to assist in achieving a more complete dissolution of the at least one colloid. Such lightening mixtures are well known in the art. [031] The at least one liquid hydrocolloid solution may be in many different forms. In one embodiment, the at least one liquid hydrocolloid solution is in the form of a viscous gel. In another embodiment, the at least one liquid hydrocolloid solution is in the form of a pumpable viscous gel. In a further embodiment, the at least one liquid hydrocolloid solution is combined with at least one gelling polymer to obtain the at least one liquid hydrocolloid solution in the form of a viscous gel. In yet another embodiment, the at least one liquid hydrocolloid solution is formed such that the colloid gelatin matrix and any encapsulated core ingredients are substantially uniformly dispersed. In yet a further embodiment, the at least one liquid hydrocolloid solution is substantially uniform in color. In still another embodiment, the at least one liquid hydrocolloid solution exhibits substantially no phase separation after three hours after mixing.

[032] In yet another embodiment, the at least one liquid hydrocolloid solution is in the form of a liquid that may retain good uniformity of the colloid gelatin matrix and any encapsulated core ingredients upon application to the surface area of a food. In yet a further embodiment, the at least one liquid hydrocolloid solution is in the form of a liquid that may be uniformly distributed across the entire surface of a food.

[033] The at least one liquid hydrocolloid solution may comprise from about 0.1% to about 5% of the at least one colloid. In one embodiment, the at least one liquid hydrocolloid solution comprises from about 0.1 % to about 4% of the at least one colloid. In another embodiment, the at least one liquid hydrocolloid solution comprises from about 0.1 % to about 2% of the at least one colloid. In a further embodiment, the at least one liquid hydrocolloid solution comprises from about 0.2% to about 2% of the at least one colloid. In yet another embodiment, the at least one liquid hydrocolloid solution comprises from about 1% to about 2% of the at least one colloid.

[034] In embodiments wherein the at least one colloid comprises at least one polymer, the at least one polymer is present in an amount less than about 25% of the at least one colloid. In one embodiment, the at least one polymer is present in an amount less than about 20% of the at least one colloid. In another embodiment, the at least one polymer is a bovine gelatin present in amount less than about 20% of the at least one colloid.

[035] The at least one liquid hydrocolloid solution may be applied to the food by any technique that is either known to the skilled artisan or hereafter discovered. In one embodiment, the at least one liquid hydrocolloid solution is applied to the food by any technique such that the solution coats the food. In another embodiment, the at least one liquid hydrocolloid solution is applied to the food by brushing the solution onto the surface. In a further embodiment, the at least one liquid hydrocolloid solution is applied to the food by dipping the food into the solution. In yet another embodiment, the at least one liquid hydrocolloid solution may be applied to the food by spraying. In such an embodiment, the spraying may be effected through the use of a spray gun, such as an A7A Airless Spray Gun manufactured by Nordson, Inc. Spraying may be conducted at any appropriate pressure level for application of the at least one liquid hydrocolloid solution to the food. In one embodiment, spraying is conducted at about 300 to about 350 psi.

[036] In one embodiment, the at least one liquid hydrocolloid solution is applied to the surface area of a food such that the at least one liquid hydrocolloid solution forms a film coating thereon. In another embodiment, the at least one liquid hydrocolloid solution is applied to the food such that a film coating formed thereon is relatively uniformly distributed across the surface or surfaces of the food to which the at least one liquid hydrocolloid solution is applied.

[037] The at least one liquid hydrocolloid solution of the present invention has been surprisingly and unexpectantly found to inhibit of the growth of bacteria on food. Without wishing to be bound by theory, it is believed that the prevention of natural juice loss caused by the liquid hydrocolloid solution is directly related to the inhibition of bacterial growth. The use of liquid hydrocolloid solutions for the purpose of inhibiting bacterial growth has not heretofore been known. This effect is both surprising and unexpected. The bacteria may be any bacteria now known or hereafter discovered whose growth on food may be inhibited through the application of at least one liquid hydrocolloid solution. The inhibition of growth of multiple strains of a bacteria is also contemplated with the present invention. In one embodiment, the bacteria is Listeria monocytogenes. In particular, liquid hydrocolloid solutions of the present invention have been found to be surprisingly effective in the inhibition of the growth of the bacteria Listeria monocytogenes.

[038] The at least one liquid hydrocolloid solution of the present invention may be used in combination with at least one biocontrol agents in order to aid in the inhibition of the growth of bacteria. In one embodiment, the at least one liquid hydrocolloid solution of the present invention is mixed with at least one biocontrol agent before the solution/agent mixture is applied to the food. In another embodiment, the at least one liquid hydrocolloid solution is added to the food after the at least one biocontrol agent. In a further embodiment, the liquid hydrocolloid solution is added to the food before the at least one biocontrol agent. In yet another embodiment, the at least one liquid hydrocolloid solution is added to the food both before and after the at least one biocontrol agent. In still a further embodiment, the at least one biocontrol agent is added both before and after the at least one liquid hydrocolloid solution.

[039] The at least one biocontrol agent may be any food-appropriate substance now known or hereafter discovered to inhibit the growth of bacteria. In one embodiment, the at least one biocontrol agent is a single strain culture of the psychotropic, heterofermentative Leuconostoc carnosum 4010. In another embodiment, the at least one biocontrol agent is B-2, a single strain culture of the psychotrophic, heterofermentative lactic acid bacterium, Lactobacillus sakei BJ-33. In a further embodiment, the at least one biocontrol agent is polylysine.

[040] The at least one liquid hydrocolloid solution of the present invention may also be useful for aiding in the retention of a food's natural juices over time during storage. In one embodiment, the at least one liquid hydrocolloid solution of the present invention aids in the retention of the a food's natural juices in which the food is stored in vacuum packaging.

[041] The at least one liquid hydrocolloid solution of the present invention may also be useful for aiding in the reduction of a food's color deterioration that occurs over time in storage. The present inventors have found that the reduction of color deterioration is more prominent in meets which tend to have a more naturally dark or red color. [042] Other than in the examples, or where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding approaches.

[043] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations and, unless otherwise indicated, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[044] By way of non-limiting illustration, examples of certain embodiments of the present disclosure are given below.

EXAMPLES Example 1

[045] Liquid hydrocolloid protein solution coated meats, poultry, and fishes according to the present invention were formed using the following process. A colloid gelatin matrix (0.2-0.8% kg) was dissolved in 1.0 kg of water at a temperature of 33° C and mechanically mixed until it was completely dissolved therein. Upon mixing, the gel solution become very viscous, though pumpable. The colloid formed was uniform in color and exhibited substantially no phase separation from the gel matrix after about three hours. The colloid protein solution was then sprayed with a Nordson A7A Spray Gun onto the surface area of a fresh beef loin, thereby coating the surface area of the beef loin with a clear protein film coating.

[046] This process was repeated and used to coat the surface area of a ready - to-eat sliced turkey breast, a ready-to-eat sliced ham, a fresh pork loin, a chicken breast, a turkey breast, beef steaks, whole chicken parts, ground meats, and sub primal meats.

[047] For each of those coating processes, the temperature of the meat or poultry was measured before and after the coating was applied and was not found to result in an increase in temperature as a result of the coating process. Example 2

[048] The control of Listeria monocytogenes on a food surface was tested using liquid hydrocolloid solutions according to the present invention, additional biocontrol agents, and mixtures thereof. In particular, ham was sliced and tested. The ham was cut using a custom-made stainless-steel borer, made from a 7.6 cm-diameter tube with one circular end sharpened as a knife, to cut circular slices, 7.5 cm in diameter and 1 cm thickness. The surface area of each slice was approximately 44 cm².

[049] Gamma radiation was used to eliminate meat biota. The ham was irradiated in clean sterile beakers, 500-mL capacity, each packed with 10 slices. The beaker was covered with a plastic film and sealed with tape. Two beakers were treated simultaneously. Irradiation was carried out at the nuclear reactor of The Ohio State University, Columbus, Ohio. Ham slices were subjected to approximately 4.5 kGy (exposure for approximately 3.7 hours). The irradiated ham slices were tested within 1 to 2 hours post-irradiation. The quality of ham slices was not adversely affected by this irradiation treatment, as judged by visual observation.

[050] Ham slices were inoculated with Listeria monocytogenes and treated with either a liquid hydrocolloid solution, a biocontrol agent, or a combination of the two. Treatment combinations and controls tested in this example are shown in Table 1. Each treatment consisted of 10 ham slices, aseptically placed in sterile Petri dishes. Slices were treated as indicated, placed in a container with a lid, and kept at 4°C. Two samples were taken from each treatment after 0, 7, 14, 21 and 28 days of refrigerated storage. The pH of a sample's surface was measured using a pH meter equipped with a surface electrode. Each sample was then placed in a stomacher bag, mixed with 50 ml_ peptone water, stomached for 2 min, and viable counts were determined by plating on Modified Oxford agar (MOX) for Listeria monocytogenes and on MRS agar for lactic acid bacteria.

[051] Inoculation of the ham slices with Listeria monocytogenes occurred by spreading a mixture of three Listeria monocytogenes strains (Scott A, OSY-8578, and OSY-328) (130 μl_) onto the surface of the ham slices to give approximately 10³ CFU/cm².

[052] The liquid hydrocolloid solution was FLAVEX 95, supplied by The Arnhem Group, suspended in sterile distilled water (0.2%) and referred to herein as simply "Flavex." That solution was sprayed to deliver 0.25 ml_ per meat slice, or approximately 113 μg/cm². [053] The biocontrol agent was "B2," a single strain culture of the psych rotrophic heterofermentative lactic acid bacterium, Lactobacillus sakei BJ-33. Two different levels of the additional biocontrol agent were tested. A "B2Hi" suspension was prepared by suspending the contents of one 25 g-packet of B2 in 500 ml_ sterile distilled water and thoroughly mixing. The suspension was sprayed to deliver 0.25 ml_ to each ham slice, resulting in an inoculum of approximately 10⁷ per cm². A "B2Lo" suspension was prepared by diluting the B2Hi suspension 1 :1000 and was sprayed to deliver an inoculum of approximately 10⁴ per cm².

[054] The liquid hydrocolloid/biocontrol agent combination suspensions, referred to herein as "Flavex-B2Hi" and "Flavex-B2Lo", were prepared according to the following procedure. The Flavex-B2Hi suspension was formed by adding 1 g of Flavex to 500 ml_ of the B2Hi suspension and thoroughly mixing. The Flavex-B2Lo suspension was formed by adding 1 g of Flavex to 500 ml_ of B2Lo and thoroughly mixing.

[055] The results of this Example 2 are presented in Table 2 (Lactic Acid bacteria) and Table 3 (Listeria monocytogenes).

Table 1 Treatment Combinations and Controls Tested in Example 2

Unt: untreated; Cont: control; Lm: Listeria monocytogenes; B2: B-2 biocontrol culture; Hi: high concentration; Lo: low concentration; Flav: Flavex; (Flav-B2): mixture of Flavex and B-2 culture. b Letters /, /7, and /77 indicate the sequence of application of the treatment. Table 2 Changes in Populations of Lactic Acid Bacteria ("LAB, "cfu/cm²) and pH on Irradiated Ham Slices After Various Treatments and During Refrigerated Storage at 4°C

[056] Irradiation treatment eliminated most of the natural microbiota on the surface of meat slices (Unt-Cont, day 0 and 7). However, after the second week of refrigerated storage, LAB population was detectable. Regardless of the inoculum size of B-2 control culture, LAB always grew to approximately 10⁸/cm² with extended storage (e.g., B2Hi-Cont, and B2Lo-Cont). There was no apparent association between the count of lactic acid bacteria on the surface of meat slices and pH values. Of the natural microbiota present in the Flavex control, a small population was found at 0 time, but the population later increased to approximately 10⁵/cm².

[057] Overall, the results of Table 2 indicate that the Flavex or Flavex+B2 treatment in accordance with the present invention was effective to inhibit the growth of Lactic Acid bacteria on the tested ham slices versus B2 alone. However, counts of the Lactic Acid bacteria in ham treated with Listeria monocytogenes may have been over estimated as some of Listeria monocytogenes inoculum may have grown on MRS agar; thus, the Lactic Acid bacteria counts presented in Table 2 may be skewed.

Table 3 Changes in Populations of Listeria monocytogenes (cfu/cm²) on Irradiated Ham Slices After Various Treatments and During Refrigerated Storage at 4°C

a See Table 1 for the treatment details. b ND = Non-detectable; detection limit for Listeria monocytogenes enumeration procedure was <6.3 x 10¹ cfu/cm'

[058] The results of Table 3 are shown in Figures 1 and 2.

[059] Listeria monogytogenes behavior as shown in Table 3 and in this Example 2 was not consistent with what had been seen previously regarding the action of B-2, which typically has a bacteriostatic rather than bactericidal effect (i.e. it prevents growth of Listeria but does not cause a decrease in the cell counts of Listeria). This inconsistency was thoroughly investigated to determine the source of this irregularity and was determined to be a change in the brand of MOX agar, which happened during the last part of the experiment. The changed MOX was too selective to allow stressed Listeria to form colonies. However, it was determined that this affected only data of week 4 (samples taken after 28 days of storage) and the two treatments that produced counts below detection level (e.g., Lm-Flav treatment). This problem was corrected in Example 3.

[060] According to Table 3, in the absence of natural microbiota on the irradiated meat surface, and with no antimicrobial treatments, Listeria population grew from 10³ cfu/cm² initially to 1.6 x 10⁶ cfu/cm² during 28 days of storage at 4⁰C (Lm-Cont). The population Listeria monocytogenes did not change appreciably on ham slices treated with the biocontrol culture (B-2) during storage for 28 days at 4⁰C (Lm-B2Hi and Lm-B2Lo). Surprisingly, the addition of Flavex enhanced the inhibitory effect of the biocontrol culture (treatments Lm-(Flav-B2Hi), Lm-(Flav/B2Lo), (Flav-B2Hi)-Lm, and (Flav-B2l_o)-I_m), regardless of the sequence of addition of Listeria and the Flavex- biocontrol mixture. In those treatments, Listeria populations decreased from 6.3x10² to 1.6x10³ cfu/cm² initially, to non-detectable levels after 28 days at 4⁰C. Adding the biocontrol culture and Flavex sequentially (e.g., Lm-B2Hi-Flav and Lm-B2Lo-Flav) apparently had a better inhibitory effect than when those agents were added as a mixture (e.g., Lm-(Flav-B2Hi)). Example 3

[061] Selected treatments from the Example 2 were repeated and the results included in this Example 3. Commercial pre-cooked turkey breast (Jennie-0 Turkey) was used. The turkey was cut using a custom-made stainless-steel borer, made from a 7.6 cm-diameter tube with one circular end sharpened as a knife. The slices used in this study were 7.5 cm in diameter and 1 cm thickness. The surface area of each slice was calculated to be approximately 44 cm². Turkey slices were treated as shown in Table 4.

[062] The experimental conditions were as follows. For the Listeria monocytogenes inoculation, a mixture of the three Listeria monocytogenes strains from Example 2 (130 μl_) was spread onto the surface of the turkey slice to give approximately 10³ CFU/cm². For the biocontrol agent, a suspension of B2 was prepared by suspending the contents of one 25 g-packet of B2 in 500 ml_ of sterile distilled water and thoroughly mixing. That suspension was diluted 1 :1000 and sprayed to deliver 0.25 ml_ to each turkey slice, resulting in an inoculum of approximately 10⁴ per cm². For the Flavex (liquid hydrocolloid solution), Flavex 95 was suspended in sterile distilled water (0.2%) and sprayed to deliver 0.25 ml_ per turkey slice, or approximately 113 μg/cm². For the Flavex-B2 culture combinations, 1 g of Flavex was added to 500 ml_ of B2 suspension and prepared as described in Example 2. The mixture was thoroughly mixed. Table 4 Treatment Combinations and Controls Tested in Example 3

a Unt: untreated; Cont: control; Lm: Listeria monocytogenes; B2: B-2 biocontrol culture; Flav: Flavex; (Flav-B2): mixture of Flavex and B-2 culture. bThe letters / and /7 indicate the sequence of application of the treatment.

Table 5 Changes in Populations of Listeria monocytogenes (cfu/cm²) on Turkey Slices After Various Treatments and During Refrigerated Storage at 4°C.

See Table 1 for the treatment details. Non-detectable. [063] The results of Table 5 are displayed in Figure 3.

[064] The B2 culture, with or without Flavex, inhibited the growth of Listeria monocytogenes on sliced turkey, but it did not eliminate the inoculated pathogen. Flavex alone surprisingly and unexpectedly produced an inhibitory effect against Listeria monocytogenes during 28 days of refrigerated storage. The product also surprisingly and unexpectedly enhanced the efficacy of B2 against Listeria monocytogenes. Example 4

[065] A 20% (g gelatin / g warm water) bovine gelatin solution spray (Lot # 31083105) was sprayed onto the surface area of sample beef loins. The liquid hydrocolloid solution-coated beef samples showed a significant reduction in purge loss of natural juices when compared to non-coated controls, as shown in the graph in Figure 4. The coated samples were also significantly darker, redder, and had less color change when compared to controls. The results of these tests are depicted in Figures 5, 6, and 7. In an effort to control or decrease the margin of error, and hence the size of the error bars represented in each of Figures 5, 6, and 7, each data point represented in Figures 5, 6, and 7 was based on 5 measurements at different locations on each of 4 different pieces of beef loin. Thus, each data point represents a total of 20 measurements. The measurements were conducted according to the standard Hunter Lab scale, where L^* is light/dark, a^* is red/green, b^* is yellow/blue, and Delta E is equal to the change in L^* squared plus the change in a^* squared plus the change in b^* squared. Hence, the FLAVEX-coated samples had less natural juice purge and less color deterioration. [066] Analysis of three different types of fresh meat products — pork loins, chicken breasts, and salmon fillets — displayed similar results as the coated beef loins. The coated pork, salmon, and chicken samples had a significant reduction in juice purge when compared to controls. The coated pork and salmon showed a slight but not significant reduction in color deterioration when compared to controls and no difference in lipid oxidation. Those results suggested that certain foods, such as meats, poultry, and fish, with darker natural colors will exhibit greater reductions in color loss due to the application of the liquid hydrocolloid solution. Example 5

[067] Beef samples were stored for 14 days and were analyzed by 50 people (panelists) per day for sensory testing at days 1 , 7, and 14. The panelists were first presented with 2 samples; 1 control (non-liquid hydrocolloid coated sample), and 1 experimental (liquid hydrocolloid-coated sample according to the present invention). The panelists were asked to determine which raw sample they preferred for overall appearance, level of redness, and level of freshness. The panelists were then presented with 2 raw samples to determine which sample they preferred for overall odor. The panelists were then given 2 cooked samples to determine which cooked samples they preferred for overall appearance, odor, preference, flavor, and tenderness. The cooked samples were cooked for 2 min on double-sided grills (George Foreman contact grill GRP99, Salton, Inc., Lake Forest, IL) so that both sides of the sample were exposed to the heat for the same amount of time. The grill was set at 190.6 ⁰C. Finally, panelists were asked to provide their age, gender, purchase and consumption frequency of fresh meat products (at least once a week, once every two weeks, once a month, once every 6 months, rarely (less than once every 6 months), or never), and type of meat product (fresh, frozen, or processed) that they most-often purchase. Each of the 2 samples was assigned a different 3-digit, random number in order to make the

control and the experimental samples undistinguishable from one another.

Table 6 Sensory results of control and liquid hydrocolloid-coated beef

Control: non-liquid hydrocolloid coated samples. Exp.: liquid hydrocolloid-coated sample according to the present invention. NSD: no significant difference found between control and experimental samples.

Table 7 Sensory results of control and liquid hydrocolloid-coated beef

Control: non-liquid hydrocolloid coated samples. Exp.: liquid hydrocolloid-coated sample according to the present invention. NSD: no significant difference found between control and experimental samples. [068] The experimental coated beef was found to be redder than the control beef at days 1 , 7, and 14 by sensory analysis. Sensory panelists preferred the smell of the raw control after 1 and 14 days of storage, and found no significant difference between the smell of the raw control and experimental-coated sample after 7 days of storage. Additionally, panelists found no significant difference between the smell and flavor of the cooked control and experimental-coated samples at 1 , 7 and 14 days of storage. Sensory panelists found no significant difference between the flavor, smell, and overall preference of the cooked controls and experimental-coated samples. Without wishing to be bound by theory, it is believed that the liquid hydrocolloid coating did not contribute its own flavor/odor to the cooked sample since it melts during cooking. In addition, the level of lipid oxidation was equivalent in both of the samples.

[069] In summary, sensory evaluation of beef confirmed that raw experimental- coated samples are redder than raw non-coated controls after storage for 14 days. Sensory also found that there was no noticeable difference between the cooked experimental-coated samples and the cooked non-coated samples in appearance, odor, flavor, tenderness, or in an overall comparison. Hence, the gelatin coat can be used by the meat industry to aide in the inhibition of the growth of bacteria without negatively affecting the cooked end-product.

Claims

WHAT IS CLAIMED IS:

Claim 1 : A method of inhibiting the growth of bacteria on a food surface, comprising applying to the food at least one coating comprising at least one liquid hydrocolloid solution.

Claim 2: The method of claim 1 , wherein the at least one liquid hydrocolloid solution comprises at least one polymer capable of forming a stable polymer gelatin.

Claim 3: The method of claim 2, wherein the at least one polymer is selected from the group consisting of animal proteins, plant polysaccharides, animal glues, collagens, wheys, caseins, starches, gums, and hydrolysates.

Claim 4: The method of claim 3, wherein the polymer is animal protein.

Claim 5: The method of claim 2, wherein the at least one liquid hydrocolloid solution further comprises at least one core food processing ingredient.

Claim 6: The method of claim 5, wherein the at least one core food processing ingredient is selected from the group consisting of flavor oils, oleoresins, spices, vitamins, and colorants.

Claim 7: The method of claim 1 , wherein the bacteria is Listeria monocytogenes.

Claim 8: The method of claim 1 , wherein the at least one liquid hydrocolloid solution is applied to at least one surface of the food.

Claim 9: The method of claim 1 , further comprising packaging the coated food in a vacuum sealed package.

Claim 10: The method of claim 1 , wherein the food is chosen from the group consisting of meat, fish, and poultry. Claim 11 : The method of claim 10, wherein the food is a ready-to-eat food product.

Claim 12: The method of claim 10, wherein the food is a case-ready food product.

Claim 13: The method of claim 10, wherein the food is a sliced food product.

Claim 14: The method of claim 10, wherein the meat is chosen from the group consisting of beef, pork, lamb, bison, and venison.

Claim 15: The method of claim 14, wherein the meat is beef.

Claim 16: The method of claim 10, wherein the poultry is chosen from the group consisting of chicken, turkey, duck, goose, and ostrich.

Claim 17: The method of claim 10, wherein the fish is chosen from the group consisting of sole, catfish, flounder, salmon, tuna, cod, snapper, trout, whiting, red snapper, grouper, mahi mahi, and bass.

Claim 18: The method of claim 17, wherein the fish is salmon.

Claim 19: The method of claim 1 , further comprising applying to the food at least one biocontrol agent.

Claim 20: The method of claim 19, wherein the at least one coating comprising the at least one biocontrol agent.

Claim 21 : A method of inhibiting the growth of Listeria monocytogenes on a food, comprising applying to the surface of the food at least one coating comprising at least one liquid hydrocolloid solution, wherein the food is chosen from the group consisting of meat, poultry, and fish.

Claim 22: The method of claim 21 , wherein the at least one liquid hydrocolloid solution comprises at least one polymer capable of forming a stable polymer gelatin. Claim 23: The method of claim 22, wherein the at least one polymer is selected from the group consisting of animal proteins, plant polysaccharides, animal glues, collagen, whey, casein, starches, gums, and hydrolysates.

Claim 24: The method of claim 23, wherein the at least one polymer is animal protein.

Claim 25: The method of claim 22, wherein the at least one liquid hydrocolloid solution further comprises at least one core food processing ingredient.

Claim 26: The method of claim 25, wherein the at least one core food processing ingredient is selected from the group consisting of flavor oils, oleoresins, spices, vitamins, and colorants.

Claim 27: The method of claim 21 , wherein the food is selected from the group consisting of a ready-to-eat food product, a case-ready food product, and a sliced food product.

Claim 28: The method of claim 27, wherein the food is a ready-to-eat food product.

Claim 29: The method of claim 27, wherein the food is a case-ready food product.

Claim 30: The method of claim 27, wherein the food is a sliced product.

Claim 31 : The method of claim 27, further comprising packaging the coated food in a vacuum sealed package.

Claim 32: The method of claim 21 , wherein the food is meat.

Claim 33: The method of claim 32, wherein the meat is selected from the group consisting of beef, pork, lamb, bison, and venison.

Claim 34: The method of claim 21 , wherein the food is poultry. Claim 35: The method of claim 34, wherein the poultry is chosen from the group consisting of chicken, turkey, duck, goose, and ostrich

Claim 36: The method of claim 21 , wherein the food is fish.

Claim 37: The method of claim 36, wherein the fish is chosen from the group consisting of sole, catfish, flounder, salmon, tuna, cod, snapper, trout, whiting, red snapper, grouper, mahi mahi, and bass.

Claim 38: The method of claim 21 , further comprising applying to the food at least one biocontrol agent.

Claim 39: The method of claim 38, wherein the at least one coating comprises the at least one biocontrol agent.

Claim 40: A method of inhibiting the growth of Listeria monocytogenes on food, comprising applying to the surface of a food selected from the group consisting of meat, poultry, or fish at least one coating comprising at least one liquid hydrocolloid solution, and wherein the food exhibits at least one of a decrease in natural juice loss and a decrease in color deterioration.