WO2002026059A2

WO2002026059A2 - Method for preserving food products using biological modified atmosphere packaging

Info

Publication number: WO2002026059A2
Application number: PCT/US2001/030187
Authority: WO
Inventors: James T. C. Yuan
Original assignee: L'air Liquide Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2000-09-29
Filing date: 2001-09-27
Publication date: 2002-04-04
Also published as: AU2002211273A1; WO2002026059A3

Abstract

A packaged food product and a method for making a packaged food product and preserving a food product using biological modified atmosphere packaging includes applying a bioactive culture to the food product prior to sealing the food product within a CO2-enriched gas atmosphere. In accordance with the invention, the CO2-enriched gas atmosphere combines with the bioactive cultures to reduce the growth of pathogenic microorganisms. In addition to CO2, other modified-atmosphere-packaging (MAP) gases, such as N2, O2 and Noble gas and mixtures of Nobel gases, can be used in combination with bioactive cultures to reduce the growth pathogenic microorganisms during storage of the food product.

Description

METHOD FOR PRESERVING FOOD PRODUCTS USING BIOLOGICAL MODIFIED ATMOSPHERE PACKAGING

FIELD OF THE INVENTION

This invention relates, in general, to food preservation and, more particularly, to packaged food products and to methods for making packaged food products and preserving food products using modified atmosphere packaging.

BACKGROUND OF THE INVENTION

As the demand for preservation methods of food products continues to grow, there is an increasing need for advances in food preservation technology. To meet the increasing demand levels for food products by both consumers and retail businesses, packaged food suppliers must deliver food products to retail outlets that will remain fresh for several days at a minimum, and preferably, for one week or longer. In addition to providing food products having extended shelf life, food producers also must provide a safe product that resists growth of pathogens and ideally remain free of pathogenic microorganisms.

In addition to fruits and vegetables, microbial contamination represents the primary mechanism for spoilage of food products, such as meats. Most kinds of food products are susceptible to both spoilage microorganisms and pathogenic microorganisms. Spoilage microorganisms result in deterioration in the color, texture, taste and smell of the food product. The presence of pathogenic microorganisms can lead to potentially deadly diseases when the food products are consumed. For example, Salmonella and Escherichia coli (E. coli) outbreaks have led to substantial loss of human life and severe economic loss for large sections of the food processing industry. Given the increase in world population and the continued demand for package food products, there is an increasing need for an effective means of assuring the production of safe food products. Modified atmosphere packaging (MAP) is a food preservation method that has been practiced for many years. The packaging of food using a MAP process involves packing the food products, most commonly fruits and vegetables, in a container having a gas atmosphere that reduces cell respiration. Common MAP gases include CO₂, N₂, 0₂ and other gases which have been shown to have an influence on food, such as the Noble gases. By packaging fruits and vegetables using a MAP process, cell respiration is reduced, thus avoiding the rapid depletion of oxygen in the package. If the oxygen level becomes very low, health threatening anaerobic pathogens, such as C. botulinum, can grow on the food products.

Currently, food manufacturers package their products using a MAP process that relies on strict temperature management to retard microbial growth. However, if temperatures are not maintained within relatively narrow refrigeration temperatures (e.g., 2-5° C), the MAP gases can lose their effectiveness at preventing the growth of pathogenic microorganisms. Also, while refrigeration temperatures slow the growth of most pathogenic microorganisms, some microorganisms will continue to multiply even at low storage temperatures. Given a sufficiently long storage time, even at refrigeration temperatures, the number of microorganisms may increase in the products to a level sufficient to cause human illness.

While MAP processing techniques are effective at minimizing microbial outgrowth under controlled temperature conditions, the pathogenic nature of common bacteria associated with food spoilage necessitates further development of food processing technology. In particular, food-manufacturing processes are needed that are less sensitive to variations in storage temperature.

SUMMARY OF THE INVENTION

The present invention is for a packaged food product, and a method of making of making a packaged food product and preserving food products using biological modified atmosphere packaging. In one embodiment of the invention, bioactive cultures, such as lactic acid bacteria, are applied to the food product, or to inner surfaces of a food container, or both, prior to sealing the food product in a CO₂-enriched gas atmosphere. Under controlled refrigerated conditions, the bioactive cultures remain dormant in the food products. The cultures will not grow and they remain colorless, odorless and tasteless. However, if the food product is removed from a refrigerated temperature environment for an extended period of time, or should the refrigeration systems in which the food products are stored fail, the bioactive cultures will rapidly grow in a CO₂-enriched atmosphere. Under rapid growth conditions, the bioactive cultures will produce acidulents, such as lactic acids, and reduce the pH of the food product. Additionally, at elevated temperatures, the bioactive cultures will produce functional bi-products that inhibit or kill pathogenic microorganisms. By incorporating bioactive cultures into a MAP food packaging process, the microbial quality of packaged foods can be enhanced and food safety can be improved. In accordance with another embodiment of the invention, a bioactive culture that produces an acidulent upon exposure to a temperature above or about room ambient temperature is applied to the food product. The food product is then sealed within a CO -enriched gas atmosphere. The CO_2--enriched gas atmosphere promotes the growth of the bioactive cultures at a temperature above or about room ambient temperature. The bioactive cultures can be selected from a wide variety of bacteria, such as lactic acid bacteria, Aerococcus, Microbactirum and Propionibacterium. The lactic acid bacterium include, but are not limited to, Carnobacteriυm, Enterococcus, Lactococcus, Lactobacillus, Lactosphaerea, Leuconostoc, Oenococcus, Pediococcus, Streptocossus, Vagococcus and Weisella.

The addition of CO₂-enriched gas provides a favorable environment for the growth of the bioactive cultures at non-refrigeration temperatures. Additionally, the CO₂-enriched gas also provides the traditional benefits of MAP gas technology, including retardation of the growth rate of spoilage microorganisms and reducing chemical degradation and other quality deterioration, such as loss of color, flavor, aroma, appearance, texture and chemical stability. The CO₂-enriched gas is preferably a gas mixture having an elevated concentration of CO₂ and a balance of N₂, O₂ and/or a Noble gas, such as Ar, Kr, Xe, and Ne.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a plot of the logarithm of E. coli bacteria count versus storage time at about 7° C. for two control food samples packaged in air and one food sample packaged in accordance with one embodiment of the invention;

FIG. 2 is a plot of the logarithm of E. coli bacteria count versus storage time at about 25° C. for two control food samples packaged in air and one food sample packaged in accordance with one embodiment of the invention; FIG. 3 is a plot of pH values versus storage time at about 25° C. for two control food samples and one food sample packaged in accordance with the invention;

FIG. 4 is a plot of the logarithm of E. coli bacteria count versus storage time at about 7° C. for a first control food sample packaged in air, a second control food sample packaged in a 50/50 volume % mixture of CO₂ and N₂, and a food sample packaged in accordance with one embodiment of the invention; and

FIG. 5 is a plot of the logarithm of bacteria count versus storage time at about 25° C. for a control food sample packaged in air and a food sample packaged in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In a preferred embodiment of the present invention, a bioactive culture is applied to a food product that is then subjected to a MAP gas process. As used herein, the terms "food product and food products" apply to a variety of food substances, including fruits, vegetables, grains, poultry, meat, seafood, prepared foods, and ready-to-eat foods and the like. Prior to beginning the process, the food products can be placed in a variety of containers including barrier or permeable containers, barrier or permeable trays, and the like. Additionally, the containers can be sealed with a barrier or permeable film. Typical gas-permeable films have an oxygen gas permeability of about 100 to about 6,000 cc/m²/24 hrs. Prior to sealing the food product within the container, a vacuum may be drawn within the processing apparatus to remove air from the container. Then, the container is flushed with a gas mixture that preferably has a CO₂ concentration of about 0.2% to about 100% by volume. The balance of the gas mixture can be one or more of N₂, O₂, and/or a Noble gas, such as Ar, Kr, Xe, and Ne, and Nobel gas mixtures.

It is known that certain concentrations of Noble gases above that found in air are effective at preserving the color of red meat and meat products. For example, Ar in a concentration of at least about 1% by volume in combination with CO₂ or O₂, or both, effectively preserves the color of packaged red meat products. Additionally, other Nobel gases such as Kr, Xe, and Ne at concentrations of at least about 0.05% by volume are also effective. Such a description can be found in commonly-assigned U.S. patent No. 6,113,962, which is incorporated by reference herein. Additionally, Nobel gases are effective in preserving organoleptic properties of fruit juices, vegetables, chocolate, coffee, edible oils, and the like, as taught in commonly-assigned, published European Patent Applications EP 0587877 (pending U.S. application serial no. 08/291 ,741 ), EP 0586690 (pending U.S. application serial no. 08/232,460), EP 0587869 (pending U.S. application serial no. 08/169,709) and EP 0587868 (pending U.S. application serial no.

07/982,496), which are incorporated by reference herein. Accordingly, it is within the scope of the present invention that Nobel gases or mixtures of Nobel gases be present at concentration levels that function to preserve the organoleptic properties of packaged food products. In accordance with the invention, the bioactive cultures can be applied directly to food products, or to the inner surfaces of food packaging, or to both. Also, the bioactive cultures can be applied to an inner surface of a barrier or permeable film used to seal the package. The bioactive cultures can be applied either before or after placing the food product in a package, but in any event before sealing the package with a barrier or permeable film.

Further, the bioactive cultures can be applied in a variety of forms, including a liquid, a freeze-dried power, and the like. Additionally, the bioactive cultures can be applied to the food products, or package surfaces, or both, by entraining a freeze-dried powder in a MAP gas used during packaging. In a preferred embodiment of the invention, the bioactive cultures can be lactic acid bacteria, Aerococcus, Microbactirum and Propionibacterium. The lactic acid bacterium include, but are not limited to, Carnobacterium, Enterococcus,

Lactococcus, Lactobacillus, Lactosphaerea, Leuconostoc, Oenococcus, Pediococcus, Streptocossus, Vagococcus and Weisella.

Once the bioactive cultures are applied to the food product or to the packaging, a conventional MAP gas process is carried out to provide a CO₂- enriched gas atmosphere within the sealed container or tray. In a preferred embodiment, the CO₂ volumetric concentration in the MAP gas varies from about 0.2% to about 100%. In a more preferred embodiment, the MAP gas is a mixture of CO₂ and one or more of N₂, O₂ and/or a Noble gas, such as Ar, Kr, Xe and Ne. In a most preferred embodiment, the MAP gas is a mixture of CO₂ and N₂. Upon sealing the food product, the container or tray is subjected to freezing or refrigeration temperatures in the range of about -70° C. to about 20° C, and preferably about -10° C. to about 7° C.

In accordance with the invention, the bioactive cultures will remain dormant within the food product so long as a controlled refrigeration temperature is maintained. Typical food storage refrigeration system are capable of maintaining refrigeration temperatures in a range of about 0° C. to about 7° C. Temperature abuse can occur when either the temperature fluctuates widely outside of the control range, or when the temperature slowly rises to about room temperature or higher. As the food product temperature increases, the growth of the bioactive cultures will be triggered, resulting in the release of acidulent and anti-microbial compounds. During the growth of the bioactive cultures, the pH of the food product is lowered preserving the food product. For example, sufficient amounts of lactic acid can lower the pH of the food product to about 5.0 or less. At acidic pH levels, the growth of pathogenic microorganisms such as Salmonella, E. coli, and the like are retarded or inhibited. Further, once growth of the bioactive cultures is triggered, the bioactive cultures release anti-microbial compounds, such as bacteriocin, that further inhibit the growth of the pathogenic microorganisms. Also, it is important to note that certain strains of lactic acid bacteria will grow at temperatures below room temperature, only more slowly than at higher temperatures. As these bacteria grow, they will excrete lactic acid. Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative and not to limit the remainder of the disclosure in anyway whatsoever. It will be appreciated that other modifications of the present invention within the skill of those in the food processing arts can be undertaken without departing from the spirit and scope of the invention.

EXAMPLE

Several containers of "Don Miguel" brand "Chicken Rice Bowl™" food product were obtained from a local supermarket for experimental analysis. To provide a ready source of bioactive cultures, lactic acid culture strains known under the trade name, "LP" and "8014" from Chr. Hanse A/S (Horsholm, Denmark), were maintained in "Lactobacilli MRS" broth from Fisher Scientific (Pittsburgh, Pennsylvania). The lactic acid cultures were transferred to fresh

MRS broth daily and incubated for eighteen to twenty hours at about 35° C. on culture media obtained from Becton Dickinson (Sparks, Maryland). A 3- strained mixture of E. coli in beef isolates was obtained from the University of Georgia. Each E. coli strain was maintained on tryptic soy agar (TSA) slants, transferred to tryptic soy broth (TSB) and incubated on cultural media for eighteen to twenty-four hours at about 35° C. The 3-strains were combined at about equal concentrations and cell counts for each strain were about 10⁹ colony-forming-units (CFU) per milliliter.

In order to evaluate the effectiveness of the lactic acid bacteria and MAP gas combination, a series of experimental samples were prepared by mixing portions of lactic acid bacteria culture with portions of E. coli cultures. The mixed bacteria cultures were then added to "Chicken Rice Bowl™" samples to a target level and mixed in a large mixing bowl for about four minutes to homogenize the sample. After mixing the bacteria and "Chicken Rice Bowl™" samples, 50 gram portions were withdrawn from the mixing bowl and placed into BT 971 barrier trays supplied by Cryovac-Sealed Air Corp. (Duncan, South Carolina). The Experimental samples were inoculated with either lactic acid strain LP or strain 8014 by method. The control samples did not receive any bioactive cultures. Next, the barrier trays were sealed under either a 50/50 MAP gas containing about equal volumetric amounts of CO₂ and N₂ or air. The MAP gas and air flushing were carried out in a Multivac Tray Packaging Machine (Kansas City, Missouri). Each tray was than sealed with a LID 1050 barrier film from Cryovac-Sealed Air Corp. The samples were then divided into two groups and stored at either 7° C. or 25° C.

After placing the samples in storage, portions of each sample were periodically removed, and the pH of the sample portion was measured using a model 720A Orion pH meter from Orion Research, Inc. (Boston,

Massachusetts). Also, microbiological analysis was performed on each sample by blending 10 grams of the sample with 90 milliliters of sterile 0.1 % peptone water and serially diluting each sample. A one milliliter portion of each diluted sample was plated on a film known under the trade name 3M™ E. coli Count Plates Petrifilm™ prior to performing a bacteria count of E. coli colonies. Also, a one milliliter sample of each culture was placed on a film known under the trade name Aerobic Count Plates Petrifilm™ prior to performing bacteria counts for spoilage bacteria. Additionally, one milliliter dilute sample was placed on Redigel™ MRS media prior to performing a bacteria count for lactic acid bacteria. Duplicates were made of each of the foregoing plates. The E. coli and aerobic count plates were incubated at about 35° C. for about 48 hours, and the Redigel™ MRS plates were incubated at about 37° C. in a CO₂ incubator for about 48 hours. The CO₂ incubator contained an atmosphere having a CO volumetric concentration of about 5% and a relative humidity of about 93%. Upon completion of the incubation, the colonies were counted and expressed as colony forming units (CFU) per gram of sample. E. Coli Plate Counts At 7° C.

Shown in FIG. 1 is a plot of the logarithmic plate count for E. coli bacteria taken at various times over a fourteen-day incubation period for samples stored at about 7° C. The bacteria E. coli counts shown in plot 10 were taken from a sample container package in about a 50/50 volume % mixture of N₂ and CO₂ MAP gas in which the lactic acid bacteria LP had been introduced. Plot 20 shows the rise in E. coli count in control samples taken from sample containers packaged under air and to which the lactic acid bacteria strain LP had been introduced. Plot 30 shows the rise in E. coli count taken from the control sample packaged under air and in which low lactic acid bacteria was introduced.

The bacteria counts of FIG. 1 illustrate a reduction in E. coli bacteria in samples containing N₂ and CO₂ MAP gas in combination with lactic acid bacteria. In general, the lower the E. coli bacteria count, the higher the microbial quality and, potentially, the safer the food product over the normal product shelf life. Importantly, the data shown in FIG. 1 illustrate the effectiveness of the combination of MAP gas with bioactive cultures at reducing the growth of pathogenic microorganisms, and in particular, E. coli.

E. Coli Plate Counts At 25° C.

FIG. 2 illustrates E. coli plate counts taken from different samples stored at about 25° C. over a three-day period. Plot 40 shows the E. coli E. coli bacteria counts taken from samples packaged under about a 50/50 volume % mixture of N₂ and CO₂ MAP gas in which the lactic acid bacteria strain LP had been introduced. Plot 50 illustrates the E. coli count for control samples packaged under air and in which the lactic acid bacteria strain LP had been introduced. Plot 60 shows E. coli counts taken from control samples packaged under air and having no bioactive cultures. The plots shown in FIG. 2 illustrate the effectiveness of MAP gas in combination with bioactive cultures to control the growth of pathogenic microorganisms when temperature abuse occurs during storage of food products. At about 25° C, pathogenic microorganisms, such as E. coli, can rapidly grow to dangerous levels. It is an important advantage of the present invention that the growth of pathogenic microorganisms is minimized when the storage temperature rises above refrigeration temperatures.

Acidity Levels At 25° C.

FIG. 3 illustrates pH values for different samples process under three different conditions over a three-day period for samples stored at about 25° C. Plot 70 illustrates the pH values from a sample packaged under about a 50/50 volume % N₂ and CO₂ MAP gas in which the lactic acid bacteria strain LP had been introduced. Plot 80 illustrates the pH values for control samples packaged under about a 50/50 volume % mixture of N₂ and CO₂ having no bioactive cultures. Plot 90 illustrates the pH values for control samples packaged under air and having no bioactive cultures. As indicated in FIG. 3, over time, the pH values for samples packaged with lactic acid bacteria and MAP gas decrease to a lower level and decrease more rapidly than the control samples. Importantly, most spoilage and pathogenic bacteria will either not grow or grow very slowly below a pH value of about 5.0. Aerobic Plate Counts At 7° C.

FIG. 4 illustrates aerobic plate counts (APC) taken from different samples stored at about 7° C. Plot 100 shows the APC values from a sample packaged under about a 50/50 volume % mixture of N₂ and CO₂ in which the lactic acid bacteria strain LP was introduced. Plot 110 shows the APC values for control samples packaged under about a 50/50 volume % mixture of N₂ and CO₂ having no bioactive cultures. Plot 120 shows the APC values from control samples packaged under air and having no bioactive cultures.

The APC value is a general indication of microbial quality of the food product. The lower the APC, the higher the microbial quality of the food product and, potentially, the longer the shelf life of the packaged food products. Importantly, the APC values for samples packaged with lactic acid bacteria and MAP gas were lower than the corresponding values for the control samples throughout the testing period.

E. Coli Plate Counts At 25° C. With Strain 8014

FIG. 5 illustrates E. coli plate count taken from samples stored at about 25° C. over a three-day period. Plot 130 illustrates the £. coli bacteria count from samples packaged under about a 50/50 volume % mixture of N₂ and CO₂ and in which lactic acid bacteria strain 8014 were introduced. Plot 140 illustrates the E. coli bacterial count from control samples packaged under air and to which lactic acid bacterial strain 8014 was introduced. The data shown in FIG. 5 indicates that the samples packaged with a

50/50 volume percent mixture of N₂ and CO₂ have lower E. coli bacteria counts throughout the testing period. This data also demonstrates the beneficial results obtained from combining a MAP gas with a bioactive culture at reducing the growth of pathogenic microorganisms in food products. Thus, it is apparent that there has been disclosed, in accordance with the invention, a packaged food product and method for making a packaged food product and preserving food products using biological modified atmosphere packaging that fully provides the advantages set forth above. Although the product and method are described with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. For example, other types of food products, such as fruits, vegetables and beef, can also benefit from processing in accordance with the method of the invention. It is therefore intended to include within the invention, all such variations and modifications that fall within the scope of the intended claims and equivalents thereof.

Claims

A method for preserving a food product comprising: placing the food product in a container; introducing a modified atmosphere including CO₂ into the container; adding bioactive cultures in the container; sealing the container; and refrigerating the container.

2. The method of claim 1 , wherein the modified atmosphere further comprises nitrogen.

3. The method of claim 2, wherein the modified atmosphere further comprises a gas selected from the group consisting of a mixture of oxygen and a Noble gas, a Noble gas, and a mixture of Noble gases.

4. The method of claim 1 , wherein the modified atmosphere further comprises oxygen.

5. The method of claim 4, wherein the modified atmosphere further comprises a Noble gas.

6. The method of claim 1 , wherein the modified atmosphere comprises of a mixture of CO₂ and nitrogen.

7. The method of claim 1 , wherein adding bioactive cultures comprises adding a lactic acid bacteria.

8. The method of claim 7, wherein the lactic acid bacteria is selected from the group consisting of Carnobacterium, Enterococcus, Lactococcus, Lactobacillus, Lactosphaerea, Leuconostoc, Oenococcus, Pediococcus, Streptocossus, Vagococcus and Weisella.

9. The method of claim 1 , wherein adding bioactive cultures comprises adding a bacteria selected from the group consisting of Aerococcus, Microbacterium and Propionibacterium.

10. The method of claim 1 further comprising removing substantially all of the air from the container prior to introducing the modified atmosphere.

11. The method of claim 1 , wherein refrigerating the container comprises maintaining the container at a temperature of no more than about 25° C.

12. A method for preserving a food product using a biological modified atmosphere comprising: applying a bioactive culture to the food product; sealing the food product within a CO₂ -enriched gas atmosphere; and refrigerating the food product.

13. The method of claim 12, wherein applying a bioactive culture comprises applying liquidious microorganisms.

14. The method of claim 12, wherein applying a bioactive culture comprises applying dry-powder microorganisms.

15. The method of claim 12, wherein sealing the food product within a CO₂ -enriched gas atmosphere comprises sealing within a gas atmosphere having about 0.2% to about 100 % by volume CO₂.

16. The method of claim 15, wherein the CO₂ -enriched gas atmosphere further comprises nitrogen.

17. The method of claim 16, wherein the CO₂ -enriched gas atmosphere further comprises a gas selected from the group consisting of a mixture of oxygen and a Noble gas, a Noble gas, and a mixture of Noble gases.

18. The method of claim 12, wherein the CO₂ -enriched gas atmosphere further comprises oxygen.

19. The method of claim 18, wherein the CO₂ -enriched gas atmosphere further comprises a Noble gas.

20. The method of claim 12, wherein the CO₂ -enriched gas atmosphere comprises about equal volumetric amounts of CO₂ and nitrogen.

21. The method of claim 12, wherein adding bioactive cultures comprises adding a lactic acid bacteria.

22. The method of claim 21 , wherein the lactic acid bacteria is selected from the group consisting of Carnobacterium, Enterococcus,

23. The method of claim 12, wherein adding bioactive cultures comprises adding a bacteria selected from the group consisting of Aerococcus, Microbacterium and Propionibacterium.

24. The method of claim 12 further comprising removing air from the container prior to introducing the modified atmosphere.

25. A method for preserving a food product using a biological modified atmosphere comprising: applying a bioactive culture to the food product, wherein the bioactive culture produces an acidulent upon exposure to a temperature above about room ambient temperature; and sealing the food product within a CO₂ -enriched gas atmosphere to promote the growth of the bioactive cultures.

26. The method of claim 25, wherein applying bioactive cultures comprises applying a lactic acid bacteria.

27. The method of claim 26, wherein the lactic acid bacteria is selected from the group consisting of Carnobacterium, Enterococcus, Lactococcus, Lactobacillus, Lactosphaerea, Leuconostoc, Oenococcus, Pediococcus, Streptocossus, Vagococcus and Weisella.

28. The method of claim 25, wherein adding bioactive cultures comprises adding a bacteria selected from the group consisting of Aerococcus, Microbacterium and Propionibacterium.

29. The method of claim 25, wherein the modified atmosphere further comprises nitrogen.

30. The method of claim 29, wherein the modified atmosphere comprises about equal volumetric amounts of CO₂ and nitrogen.

31. The method of claim 25 further comprising placing the food product in a barrier tray prior to applying a bioactive culture.

32. The method of claim 31 , wherein sealing the food product comprises applying a barrier film to the barrier tray.

33. The method of claim 25 further comprising placing the food product in a permeable container prior to applying a bioactive culture.

34. A method of making a packaged food product using a biological modified atmosphere comprising: providing a package; applying a bioactive culture to the food product and placing the food product in the package, wherein the bioactive culture is applied at one of before and after placing the food product in a package; sealing the food product within the package, the package having a CO₂ -enriched gas atmosphere; and processing the packaged food product by one of refrigerating and freezing the packaged food product.

35. A method for making a packaged food product using a biological modified atmosphere comprising: providing a package; applying a bioactive culture to the food product and placing the food product in the package, wherein the bioactive culture is applied at one of before and after placing the food product in a package, and wherein the bioactive culture produces an acidulent upon exposure to a temperature above about room ambient temperature; and sealing the food product within the package, the package having a CO₂ -enriched gas atmosphere to promote the growth of the bioactive cultures at a temperature above about room ambient temperature.

36. A packaged food product comprising: a package having a food product therein; a bioactive culture within the package; and a CO₂ -enriched gas atmosphere sealed within the package.

37. The packaged food product of claim 36, wherein the bioactive culture resides on the food product.

38. The packaged food product of claim 36, wherein the bioactive culture resides on an inner surface of the package.

39. The packaged food product of claim 36, wherein the CO₂ - enriched gas atmosphere comprises a gas atmosphere having about 0.2% to about 100% by volume CO₂.

40. The packaged food product of claim 39, wherein the CO₂ - enriched gas atmosphere further comprises nitrogen.

41. The packaged food product of claim 40, wherein the CO₂ - enriched gas atmosphere further comprises a gas selected from the group consisting of a mixture of oxygen and a Noble gas, a Noble gas, and a mixture of Noble gases.

42. The packaged food product of claim 36, wherein the CO₂ - enriched gas atmosphere further comprises oxygen.

43. The packaged food product of claim 42, wherein the CO₂ - enriched gas atmosphere further comprises a Noble gas.

44. The packaged food product of claim 43, wherein the CO₂ - enriched gas atmosphere comprises about equal volumetric amounts of CO₂ and nitrogen.

45. The packaged food product of claim 36, wherein the bioactive cultures comprises a lactic acid bacteria.

46. The packaged food product of claim 45, wherein the lactic acid bacteria is selected from the group consisting of Carnobacterium, Enterococcus, Lactococcus, Lactobacillus, Lactosphaerea, Leuconostoc, Oenococcus, Pediococcus, Streptocossus, Vagococcus and Weisella.

47. The packaged food product of claim 46, wherein the bioactive cultures comprise a bacteria selected from the group consisting of Aerococcus, Microbacterium and Propionibacterium.