Description:TECHNICAL FIELD
[0001] The present invention is related to preservation of food product, in particular, increasing the shelf life of food product with surface treatment.
BACKGROUND
[0002] Prevention of food spoilage and food poisoning has been attempted throughout history often through trial and error. The early attempts have resulted in the adoption of such food preservation methods as the drying, salting and/or smoking of foods in order to preserve them. It has been relatively recent in recorded history that food preservation has been placed upon a scientific foundation. In the nineteenth century, work of such scientists as Louis Pasteur and Robert Koch elucidated the bacterial causes of food poisoning and spoilage and provided new methods of identifying pathogenic bacteria and of preserving food.
[0003] Present food technologists utilize an array of physical, chemical, and biological processes and agents to preserve food and prevent the transmission of disease via foodstuffs. In addition to such processes as irradiation, fermentation, pasturization, control of temperature, pH and/or water activity, a plethora of chemical agents exist. These agents include antioxidants to prevent chemical degradation of food, as well as compositions which kill or inhibit deleterious bacteria and/or other microbes thereby preserving food i.e. preventing both spoilage and the transmission of disease. Commonly employed antimicrobial chemical agents include nitrites, nitrates, sulphur dioxide, sulfites, and acids such as acetic, propionic, lactic, benzoic, and sorbic acid and their salts, wood smoke and liquid smoke, and antibiotics such as natamycin and nisin.
[0004] The problem was rooted in the pores, irregularities and other imperfections found on the surface of meat. Such pores and irregularities will often serve as fertile grounds for the development of bacterial growth. Further frustrating the success of conventional sterilization procedures, the removal of surface contamination from meat has proven difficult due also to the strong adhesion of microorganisms to the meat surface. When a wash or spray is used, many organisms tend to escape. While better results were achieved with the addition of bactericides to the spray or wash water, the improvement was slight. Even with the use of concentrated and powerful bactericides, a significant number of organisms still often survived. This occurred even when the exposure time and bactericide concentration were more than adequate to sterilize, a smooth, smple surface.
[0005] It is in light of the above, that the present invention was designed. In the most general sense, the present invention provides a means to kill microorganisms without damaging the meat product itself.
SUMMARY
[001] Embodiments of the present disclosure present technological improvements as solutions to one or more of the above-mentioned technical problems.
[002] Before the present subject matter relating to process for extending the shelf life of food product, it is to be understood that this application is not limited to the particular system described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the implementations or versions or embodiments only and is not intended to limit the scope of the present subject matter.
[003] This summary is provided to introduce aspects related to process for extending the shelf life of food product. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the present subject matter.
[004] It is noted that the present invention seeks to kill the targets in place; rather than try to remove them. In general, dead enterobacteria are not harmful to humans. These bacteria do not form spores, nor do they produce any toxins which act after their death, as do some Clostridia.
[005] In one embodiment, a meat sterilization process which avoids making any change in the interior of the meat piece. In another embodiment, process that may be used to treat uniformly any surface with a gas in a way that is both begun and ended so abruptly as to have no appreciable effect on the solid below the surface so treated.
[006] In another embodiment, novel bactericidal composition comprising in combination a Streptococcus lactis-derived or synthetic equivalent bacteriocin such as nisin, and a chelating or sequestering agent.
[007] In another embodiment, an improved process for destroying psychrotrophic spoilage bacteria on meat or meat-cuts without substantially denaturing meat protein and without adversely affecting the color, flavor or aroma of the meat.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[008] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference features and modules.
[009] Figure 1 illustrates a flow chart generally outlining the basic steps involved in the present meat treating process.
[0006] It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative methods embodying the principles of the present disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.
DETAILED DESCRIPTION
[0007] The invention will now be described with reference to the accompanying drawings and embodiments which do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
[0008] One or more embodiments are provided so as to thoroughly and fully convey the scope of the present invention to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present invention. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present invention. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
[0009] The terminology used, in the present invention, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present invention. As used in the present invention, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present invention is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
[0010] Figure 1 illustrates a flow chart generally outlining the basic steps involved in the present meat treating process. Figure 1 provides a flow chart which generally outlines the four basic steps in killing microorganisms on the surface of meat products. As shown in Figure 1, the first step involves exposing the meat product to a vacuum. The second step involves flushing the meat surface with a treatment gas. The third step involves treating the meat with the treatment gas. The fourth step involves exposing the meat again to a vacuum. The treating substance applied is a gas, such as steam, ozone, hydrogen peroxide or propylene oxide. Use of such gases avoids the difficulties concerning penetration into surface irregularities to effect microbial kill: Due to their size, these gases can enter any cavity large enough to contain a bacterium.
[0011] Gas approaches a surface in one or the other of two possible modes: Streaming or diffusion. Of these, streaming is very rapid and is motivated by pressure gradient. The other mode, diffusion, is much slower and is motivated by the concentration gradient of the gas through other gases.
[0012] During gas treatment, air, or any other non-condensible gas present, would concentrate near the treated surface as a result of being pushed up to this surface by the in rush of condensing steam, or reacting gas. This air would quickly form a layer near the surface. Additional gas must then diffuse through this layer; since it cannot stream through it. The time taken for a killing dose of gas to reach the target organisms is therefore strongly dependent on the quantity of non-condensible gases which may be between the treating gas and the target.
[0013] A novel antimicrobial composition comprising a synergistic combination of a Streptococcus-derived bacteriocin such as nisin or a Pediococcus-derived bacteriocin such as pediocin, (or a synthetic equivalent) and a chelating agent such as citric acid has been discovered to have unexpectedly good bactericidal properties especially against pathogenic bacteria such as Listeria monocytogenes. Additionally, the inventive composition surprisingly is able to prolong food shelf life by preventing food spoilage for a longer period of time than would be expected based upon the effectiveness of either component alone. Nisin is a known food preservative which is also known to be heat-stable, acid-stable and active against gram-positive bacteria. Nisin is used as a food preservative in dairy products and vegetables usually in conjunction with heat treatment. Nisin also occurs naturally in raw milk and has been used in heat processing of meat pastes. Nisin is considered to be nontoxic.
[0014] Bacteriocin produced by Pediococcus bacteria may be used in the present invention. Pediococci are lactic acid bacteria which are used as starter cultures in the manufacture of fermented sausages. Pediococci are known to inhibit the growth of both pathogenic and spoilage microorganisms. Suitable chelating (sequestering) agents include carboxylic acids, polycarboxylic acids, amino acids and phosphates. Preferred chelating agents are nontoxic to mammals and include aminopolycarboxylic acids and their salts such as ethylenediaminetetraacetic acid (EDTA) or its salts (particularly its di- and tri-sodium salts), and hydrocarboxylic acids and their salts such as citric acid.
[0015] As per preferred embodiment, a process for treating meat to destroy substantial amounts of psychrotrophic spoilage bacteria carried on the surfaces thereof, said process comprising contacting all surfaces of said meat with an aqueous solution of acetic acid having an acid concentration of from about 1-2.5% by weight, and having a temperature of from about 140°F. to 180°F. for a time period of from about 5 to 60 seconds.
[0016] All food grade acids have some beneficial effect in reducing bacterial contamination on meat surfaces, including acetic acid, citric acid, tartaric acid, fumaric acid, ascorbic acid, malic acid, succinic acid, adipic acid, and phosphoric acid. However, we have unexpectedly discovered that the use of acetic acid obtains a bacterial reduction far greater than that obtained by any other food grade acid, using comparable application parameters, and therefore, this invention is directed to the use of acetic acid.
[0017] EXAMPLE 1
[0018] Thirty grams of broiler chicken meat was cut to fit the treatment chamber. Again, the sample was painted with a suspension of Listeria innoccuans. The operating conditions were as follows:
Step Duration Conditions
Vacuum 1.0 second 00.3 psia
Flush 0.3 second
Treat 1.0 second 40.0 psia (steam)

Vacuum 1.0 second 00.3 psia

After treatment, unlike Example 1, the meat sample was found without any areas having a cooked, whitish appearance. The treated and untreated controls were washed with a sterile peptone solution and the rinses plates. Again, 104 colonies were counted in the untreated samples, whereas 100 colonies were counted in the treated samples.
[0019] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the invention.
, Claims:We claim:
1. A method for extending the shelf life of a food product, comprising the steps of:
exposing the food product to a vacuum;
flushing the food surface with a treatment gas;
treating the food with the treatment gas; and
exposing the food again to a vacuum.

2. The method of Claim 1, wherein the food product is selected from the group consisting of meats, poultry, seafood, and dairy products.

3. The method of Claim 1, wherein the treatment gas comprises a mixture of gases including nitrogen and carbon dioxide.

4. The method of Claim 1, wherein the treatment gas comprises ozone.

5. A novel antimicrobial composition for extending the shelf life of a food product, comprising a synergistic combination of:
a Streptococcus-derived bacteriocin, wherein said bacteriocin is nisin; and
at least one additional antimicrobial agent selected from the group consisting of natural antimicrobial compounds, synthetic antimicrobial compounds, and bacteriophages.

6. The antimicrobial composition of Claim 5, wherein the Streptococcus-derived bacteriocin is present in a concentration ranging from 0.1% to 5% by weight of the composition.
7. The antimicrobial composition of Claim 5, wherein at least one additional antimicrobial agent is selected from the group consisting of lysozyme, natamycin, and pediocin.

8. The antimicrobial composition of Claim 5, wherein the composition further comprises a carrier or excipient suitable for food applications.

9. A food product comprising the antimicrobial composition of Claim 5, wherein the food product is selected from the group consisting of deli meats, cheese, and dairy-based products.

10. A packaged food product comprising the antimicrobial composition of Claim 5, wherein the packaged food product is sealed in an airtight container to preserve freshness and extend shelf life.