Methods for extending the shelf life of packaged foods

Abstract

This invention relates to a method for extending the shelf life of packaged foods by killing heterotrophic B. cereus bacteria and their spores, and to packaged foods stored in a refrigerator.

Description

[Technical Field]

[0001] The present invention relates to a method for extending the shelf life of packaged food (sometimes referred to as "packaged food" or "food packaging"), and to packaged food produced thereby. [Background technology]

[0002] In today's rapidly changing society, the time constraints people face have led to the popularity of repackaged foods (REPFED) that can be stored for extended periods. These REPFEDs inherently contain bacteria and their spores, such as Bacillus cereus, Listeria monocytogenes, Streptococcus fecal, and Clostridium botulinum, which pose significant health risks to consumers. Therefore, it is necessary to reduce or remove the amount of bacteria and spores in REPFEDs. Although various methods exist to extend shelf life, their effectiveness in killing these strains and their spores is limited. One commonly used technique for extending shelf life is sterilization, which typically involves adjusting the pH of the REPFED to above 4.5. In this method, the food is intensely heated in an autoclave for about 20-40 minutes at a temperature of about 121.1-140°C. While this method can kill vegetative bacteria and their spores, it significantly impairs the overall quality of the food. Sterilized foods are well known as canned foods that can be stored for several years. Another widely recognized method, particularly for REPFED with a pH of up to 4.5, is pasteurization. During pasteurization, REPFED is briefly heated to approximately 70-90°C, eliminating vegetative bacteria while minimizing molecular and structural changes. For REPFED with a pH above 4.5, an acid or additive is used to lower the pH to below 4.5 before pasteurization. While pasteurization is effective in eliminating some vegetative bacteria such as Listeria and Streptococcus fecal, it has been observed that other specific vegetative bacteria, such as Bacillus cereus and Clostridium botulinum, can survive this treatment. Furthermore, spores of Bacillus cereus and Clostridium botulinum are known to be more heat-resistant and can survive pasteurization. In refrigerated environments, these spores germinate and multiply despite their limited growth potential, thus limiting the shelf life of pasteurized REPFED in general to just a few days.Specifically, since psychrophilic Bacillus cereus is inherently widespread (ICMSF, 1996, Microorganisms in Foods 5, Characteristics of Microbial Pathogens), it is considered a potential contaminant of REPFED. Consequently, heat treatments used for preserving refrigerated foods need to address the removal of psychrophilic Bacillus cereus spores, which are more heat-resistant than, for example, non-proteinogenic botulinum spores. Therefore, new methods are needed to further improve the microbial safety and storage stability of REPFED while minimizing the degradation of its taste and nutrients. [Overview of the project]

[0003] The present invention relates to a method for extending the shelf life of packaged foods by protecting them from bacteria, particularly spore-forming bacteria such as Bacillus cereus, and optionally Listeria monocytogenes, Streptococcus fecalis, and psychrophilic Clostridium botulinum and its spores, thereby improving the storage stability of the food and minimizing the deterioration of the sensory properties of the stored packaged foods, such as REPFED. By extending the refrigerated storage period of stored packaged foods to several weeks, months, or even years, manufacturers can supply products to domestic and export markets more efficiently and economically throughout the distribution and storage process. The shelf life of food is determined by the sensory properties of the food itself, rather than being limited by the amount of colony-forming units or bacterial growth.

[0004] Therefore, in a first embodiment, the present invention relates to a method for extending the shelf life of packaged food (food packaging), and includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C. b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds. C) A step of cooling the heated food inside the food packaging to 0-12°C within 15 minutes. In certain embodiments, the food is a resealable, refrigerated (REPFED) product.

[0005] In certain embodiments, the pH of the food product (food) or at least a portion thereof is at least 4.6. In certain embodiments, a pressure higher than atmospheric pressure is applied from outside the food packaging during at least part of step a) and / or step b), preferably the externally applied pressure is 0.1 to 1.0 bar (1 × 10⁻¹⁰) higher than the pressure inside the food packaging. 4 ~1 × 10 5 Pa) High, preferably 0.2 to 0.7 bar (2 × 10 4 ~7×10 4 Pa), for example, 0.1 to 0.3 bar (1 × 10⁻⁶ 4 ~3×10 4 Pa), for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 bar higher, and more preferably, the externally applied pressure is 0.15 to 0.25 bar (1.5 to 2.5 × 10) higher than the pressure inside the packaged food (food packaging). 4 Pa) High. It should be understood that when food inside a food package is heated to the temperature specified in step a) and / or step b), the pressure inside the food package is expected to rise to a value higher than atmospheric pressure, particularly above 1.0 bar. For example, but not limited to, a food temperature of 112°C inside the package may correspond to a pressure inside the package of approximately 1.53 bar. External pressure that is higher than the internal pressure inside the package will act to counteract the accumulated internal pressure and prevent deformation and damage to the package, particularly minute leaks at seams between different materials and expansion of the package.

[0006] In certain embodiments, before packaging and packing (closing) the food in step a), the food is preheated to a temperature of 50°C to 75°C, more preferably 55°C to 70°C, and most preferably 60°C to 65°C, especially under atmospheric pressure. In certain embodiments, the food is packaged before step a), and before packing, optionally, before and / or during any preheating.

[0007] In certain embodiments, a pressure magnetron or autoclave is used to pressurize and heat packaged food (food packaging). In certain embodiments, a pressure magnetron, autoclave, or ohmic heating is used to preheat the food.

[0008] In certain embodiments, the heated food packaging is immersed in water in order to maintain the heated food inside the packaging at 110-125°C. In certain embodiments, in step c), the heated food packaging (packaged food) is cooled using nitrogen gas (N2), cold air, cold water, or ice.

[0009] In certain embodiments, the food is packaged under a protective atmosphere, optionally under a nitrogen gas (N2) atmosphere, preferably with an oxygen content of less than 1 volume percent in the upper space of the package.

[0010] Accordingly, in a further embodiment, the present invention relates to packaged foods obtained or obtained by the methods disclosed herein. In certain embodiments, the food is a resealable, refrigerated processed food (REPFED) product.

[0011] In certain embodiments, at temperatures between 0°C and 12°C, the packaged food is free of at least heterotrophic Bacillus cereus, and optionally also free of Listeria monocytogenes and / or fecal streptococcus and / or psychrophilic botulinum, and the bacterial spores are at least fatally damaged so that the spores are no longer capable of vegetative growth of each bacterium.

[0012] In certain embodiments, the food inside the packaging is free from the vegetative bacterium *Bacillus cereus*, and its spores are at least fatally damaged. In certain embodiments, the food does not contain preservatives. [Brief explanation of the drawing]

[0013] The following description of the drawings of specific embodiments of the present invention is merely exemplary in nature and is not intended to limit the teachings, application or use of the present invention.

[0014] [Figure 1] It is a radar chart showing the sensory evaluation results of red cabbage processed by three different methods. Method 1 (dark gray), Method 2 (gray), Method 3 (light gray). Each value is the average value (n=10) of sensory evaluation performed on a 0 to 100% scale. Mode for Carrying Out the Invention

[0015] Before describing the products, compositions, uses and methods of the present invention, it should be understood that the present invention is not limited to the specific products, compositions, uses, methods or combinations described, because such products, compositions, uses, methods and combinations may naturally vary. It should also be understood that the terms used herein are not intended to be limiting, since the scope of the present invention is limited only by the appended claims.

[0016] As used herein, the singular forms "a", "an" and "the" include both singular and plural referents unless the context clearly dictates otherwise. As used herein, the terms "comprise", "have" and "consist of" are synonymous with "include", "contain", and are inclusive or open-ended, and do not exclude additional, unrecited components, elements or method steps. It will be understood that the terms "comprising", "comprises" and "comprises of" as used herein include the terms "consisting", "consists" and "consists of".

[0017] When specifying a numerical range using endpoints, the range should include not only the endpoints themselves, but also all the numbers and fractions contained within that range. As used herein, the terms “about” or “approximately” refer to measurable values ​​such as parameters, quantities, or durations, and shall include variations of + / -10%, preferably + / -5%, more preferably + / -1%, and even more preferably + / -0.1% or less from the specified value, insofar as they are appropriate for carrying out the disclosed invention. It should be understood that the values ​​themselves referred to by the modifiers “about” or “approximately” are also specifically and preferably disclosed.

[0018] The terms “one or more” or “at least one,” for example, one or more or at least one member of a group of members, are self-evident, but by further example, the terms are extended to refer, among other things, to any one of the members, or any two or more of the members, such as three or more, four or more, five or more, six or more, or seven or more of the members, and up to all of the members.

[0019] All references cited herein are incorporated herein by reference in their entirety. In particular, the teachings of all references specifically referenced herein are incorporated herein by reference. Unless otherwise defined, all terms used in the disclosure of the present invention (including technical and scientific terms) have meanings that are generally understood by those skilled in the art to which the present invention pertains. Further guidance includes definitions of terms to better understand the teachings of the present invention.

[0020] The following text provides a more detailed definition of various aspects and embodiments of the present invention. Each of the aspects and embodiments thus defined may be combined with other aspects or embodiments unless expressly otherwise indicated. In particular, features indicated as preferred or advantageous may be combined with other features indicated as preferred or advantageous.

[0021] Throughout this specification, the phrase “one embodiment” or “embodiment” means that a particular feature, structure or characteristic described in relation to that embodiment is included in at least one embodiment of the present invention. Therefore, the occurrence of the phrase “in one embodiment” or “in an embodiment” in various parts of this specification does not necessarily refer to the same embodiment, although it may. Furthermore, certain features, structures or characteristics can be combined in any suitable way in one or more embodiments, as will be apparent to those skilled in the art from this disclosure. Moreover, in some embodiments described herein, combinations of features of different embodiments that include some features included in other embodiments but not others are within the scope of the present invention and are intended to form different embodiments, as will be understood to those skilled in the art. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0022] As supported by the experimental section illustrating specific representative embodiments of the present invention, the inventors provide a favorable application of a method for extending the shelf life of packaged foods, such as REPFED. This method offers the remarkable advantage of significantly extending the shelf life of packaged foods while maintaining or minimizing the deterioration of quality and taste. By applying this method, the shelf life of storage packaged foods can be extended from a few days to several weeks, months, and even up to a year. This innovative approach eliminates the need for preservatives, making it a highly advantageous method for long-term food storage. This method effectively removes pathogenic microorganisms such as heterotrophic Bacillus cereus, and optionally heterotrophic Listeria monocytogenes, Streptococcus fecal, and Clostridium botulinum, at least inactivating the spores of these bacteria to prevent their migration to active trophic bacteria, thus ensuring the microbial safety of packaged foods and significantly reducing the risk of food poisoning associated with these harmful microorganisms. Furthermore, this method promotes sustainability by minimizing food waste and maximizing food use and resource management.

[0023] Therefore, one aspect of the present invention provides a method for extending the shelf life of packaged food (food packaging), the method comprising the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 15 minutes.

[0024] The method according to the present invention enables the storage and long-term preservation of packaged foods without the addition of preservatives, and kills heterotrophic Bacillus cereus, and optionally Listeria monocytogenes, Streptococcus fecalis, and Clostridium botulinum and their spores, or at least fatally damages the spores of said bacteria.

[0025] As used herein, the terms “preservation,” “preserving,” and “preserve” generally refer to a set of techniques and methods used to extend the shelf life of packaged food products and maintain their quality, safety, and freshness over a period of time. Methods for extending shelf life generally aim to reduce the growth of microorganisms, enzymatic reactions, and chemical changes that cause spoilage, leading to deterioration of food, loss of nutritional value, and the presence of harmful bacteria.

[0026] As used in this book, the terms “conservation,” “conserving,” and “conserve” generally refer to a comprehensive set of processes and techniques aimed at minimizing food waste, optimizing resource use, and promoting sustainability throughout the food supply chain. The concepts of “preservation,” “storage,” and “safekeeping” extend to various means, such as food preservation and processing. In one embodiment, the food is a resealable, refrigerated processed food (REPFED) product.

[0027] As used herein, the term "lethally damaged" refers to spores that are not killed but damaged to such an extent that they cannot germinate in food products stored at a maximum of 10°C, preferably at a maximum of 4°C. In an embodiment, the bacterial spores are lethally damaged at least to the extent that the bacteria can no longer undergo vegetative growth in food products stored at a maximum of 12°C, preferably at a maximum of 10°C, more preferably at a maximum of 4°C.

[0028] In an embodiment, the pH of the food product, or at least a portion thereof, is at least 4.6, more preferably 4.6 to 7.0, for example 5.0 to 7.0, most preferably 4.6 to 6.0, for example 5.0 to 6.0.

[0029] In a specific embodiment, a pressure higher than atmospheric pressure is applied from outside the packaged food product (food package) during at least part of step a) and / or step b). For example, a pressure higher than atmospheric pressure may be applied to the packaged food only during step a) and may not be applied during step b). In another example, a pressure higher than atmospheric pressure may be applied to the packaged food during both step a) and step b). For example, the pressure higher than atmospheric pressure may be applied to the packaged food during the entire period of step a), or during at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the duration of step a). Independently, the pressure higher than atmospheric pressure may be applied to the food package during the entire step b), or during at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the duration of step b).

[0030] In an embodiment, the pressure applied from the outside is 0.1 to 1.0 bar (1×10 4 ~1×10 5 Pa), preferably 0.2 to 0.7 bar (2×10 4 ~7×10 4 Pa), for example 0.1 to 0.3 bar (1×10 4 ~3×10 4The pressure applied from the outside should be higher than the pressure inside the food packaging, for example, about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 bar, and more preferably, the externally applied pressure should be 0.15 to 0.25 bar (1.5 to 2.5 × 10) higher than the pressure inside the food packaging. 4 Pa) High.

[0031] In one embodiment, the food packaging can be immersed in water during pressurized heating, and the water temperature can be increased during pressurized heating.

[0032] As used herein, the term "pressurized heating" refers to a process that involves applying external pressure to food inside a package, which is higher than atmospheric pressure, causing the temperature of the food inside the package to rise to over 100°C while the package is exposed to the external pressure.

[0033] In one embodiment, before step a) and before packaging, the food is preheated to a temperature of 50-75°C, more preferably 55-70°C, and most preferably 60-65°C under atmospheric pressure. Thus, one embodiment of this method includes preheating the food to a temperature of 50-75°C under atmospheric pressure before step a), and packaging the food to provide packaged food (food packaging). The preheating temperature is preferably 55-70°C, and most preferably 60-65°C.

[0034] In one embodiment, the food is packaged before step a) and degassed before sealing. Thus, one embodiment of this method includes degassing the food before step a). Optionally, if the food is also preheated, degassing may be performed before and / or during preheating, preferably during preheating. The food may also be stirred during preheating to speed up degassing. In certain embodiments, when preheating is performed using ohm heating, it is preferable that the food product (food) be degassed before preheating to ensure that the product being preheated does not substantially contain air bubbles that could interfere with the ohm heating process.

[0035] As used herein, the terms “degassed,” “degassed,” and “degass” refer to the process of removing air present in food. Several processes exist for degassing food, including, but not limited to, heating the food to reduce the solubility of gases. In some embodiments, degassing is performed under atmospheric pressure by heating the food to a temperature of 50°C to 75°C, more preferably 55°C to 70°C, and most preferably 60°C to 65°C. If the food is not homogeneous and contains a liquid portion and solid food pieces dispersed / present within it, it is assumed that air is removed first from the liquid portion and then from the food pieces.

[0036] In one embodiment, during the food packaging process, the food is placed in an open container or receiver, such as a tray or cup. Subsequently, a lid, cover sheet, or cover film is attached to the container, sealing the opening of the container, particularly by making it airtight. In the resulting packaged food (food packaging), there is clearly an upper space between the surface of the food and the lid, sheet, or film. In other words, the upper space corresponds to the enclosed portion within the sealed container or receiver that is not occupied by the food. To improve storability and quality, it is desirable that the upper space be filled with nitrogen gas or CO2.

[0037] As used herein, the term “packaging” generally refers to sealable bags such as trays and cups, and open containers or receptacles that can be sealed with a lid, sheet, or film. Packaging can be made from one or more materials, preferably heat-resistant and pressure-resistant materials, such as, but not limited to, metals such as aluminum, glass, and plastics such as polypropylene (PP), low-density polyethylene (LDPE), high-density polyethylene (HDPE), polystyrene (PS), and polyethylene terephthalate (PET). Open containers or receptacles may be made of a different material than the lid, sheet, or film. Various types of lids, sheets, and films can be used to seal containers and receptacles. This ensures the product's original appearance and prevents contamination. These lids, sheets, and films may be designed to be easily peeled off to open the packaging, or they may require other tools such as a knife or scissors. Specific examples of lids, sheets, or films include stretch lids, sheets, or films and heat-seal lids, sheets, or films used to cover the open surface of a container or receptacle.

[0038] In step a), the packaged food is heated by pressure heating to a temperature of 110-125°C, preferably 110-120°C or 111-120°C, more preferably 110-117°C or 111-117°C, more preferably 110-115°C or 111-115°C, and even more preferably 112-120°C, 112-117°C or 112-115°C.

[0039] In an exemplary embodiment, a method for extending the shelf life of packaged food (food packaging or packaged food) includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 111-125°C; b) A step of holding the heated food inside the food packaging at 111-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 2 hours.

[0040] The time required to heat packaged food can vary depending on various factors, including the initial temperature of the food before pressurized heating, the dimensions of the food being packaged, the composition of the food, and the packaging materials used.

[0041] In some embodiments, a pressure magnetron or autoclave is used for pressurized heating of packaged food and, if necessary, for preheating. Typical radio frequencies emitted from current magnetrons are 2450 MHz or 915 MHz.

[0042] In step b), the temperature of the heated food inside the food packaging is maintained at 110-125°C, preferably 110-120°C, or 111-120°C, more preferably 110-117°C, or 111-117°C, more preferably 110-115°C, or 111-115°C, even more preferably 112-120°C, or 112-117°C for 10-60 seconds, 10-55 seconds, 10-50 seconds, 10-45 seconds, preferably 10-40 seconds, more preferably 10-35 seconds, even more preferably 10-30 seconds, 15-60 seconds, 15-55 seconds, 15-50 seconds, 15-45 seconds, preferably 15-40 seconds, more preferably 15-35 seconds, and even more preferably 15-30 seconds. To maintain the temperature of the heated food, the heated food packaging can be immersed at least partially, or preferably completely, in water at the temperatures specified above. By immersing food packaging heated in a pressurized environment in water, the occurrence of burnt edges and cold areas can be minimized and even completely eliminated.

[0043] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-55 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 2 hours.

[0044] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 111-125°C; b) A step of holding the heated food inside the food packaging at 111-125°C for 10-55 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 2 hours.

[0045] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of maintaining the heated food inside the food packaging at 110-125°C for 10-50 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C within 2 hours.

[0046] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 111-125°C; b) A step of holding the heated food inside the food packaging at 111-125°C for 10-50 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 2 hours.

[0047] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-45 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 2 hours.

[0048] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 111-125°C; b) A step of maintaining the heated food inside the food packaging at 111-125°C for 10-45 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C within 2 hours.

[0049] In one embodiment, in order to maintain the temperature of the heated food inside the food packaging at the temperature specified above, the food packaging is subjected to a pressure 0.1 to 1.0 bar (1 × 10) higher than the pressure inside the food packaging. 4 ~1 × 10 5 Pa), preferably 0.2 to 0.7 bar (2 × 10 4 ~7×10 4 Pa) High pressure, for example 0.1-0.3 bar (1 x 10⁻⁶ 4 ~3×10 4 (Pa) Immerse in water in a pressure magnetron maintained at a high pressure, e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 bar. For example, when heating and holding food at a temperature of 110–117°C, the pressure inside the heated packaging may be 1.2–1.8 bar; at 110–115°C, the pressure inside the heated packaging may be 1.2–1.6 bar; and at 112°C, the pressure inside the heated packaging may be approximately 1.5 bar.

[0050] Temperature and pressure data loggers can be used to track the temperature and pressure of food during pressurized heating and temperature maintenance. The data loggers can be installed inside the food packaging and record the temperature and pressure conditions throughout the entire process of pressurized heating and temperature maintenance of the food, ensuring that the food is heated to the desired temperature and maintained for the desired time. Once the process is optimized and tested for specific types of food and packaging, it is understood that the processing process can be carried out on an industrial scale with optimized settings, even without installing temperature and pressure data loggers inside the packaging. Optionally, for quality control purposes, temperature and pressure data loggers may be included in a small subset of the processed packaging.

[0051] In step c), the heated food package is cooled to 0-12°C in less than 2 hours, preferably less than 75 minutes, more preferably less than 60 minutes, more preferably less than 20 minutes, more preferably less than 19 minutes, more preferably less than 18 minutes, more preferably less than 17 minutes, more preferably less than 16 minutes, even more preferably less than 15 minutes, or in preferred order, less than 14 minutes, less than 13 minutes, less than 12 minutes, less than 11 minutes, less than 10 minutes, less than 9 minutes, less than 8 minutes, less than 7 minutes, less than 6 minutes, less than 5 minutes, less than 4 minutes, less than 3 minutes, less than 2 minutes, or less than 1 minute. Thus, the temperature of the heated food inside the package decreases from the starting temperature of 110-125°C to the final temperature of 0-12°C within the specified time.

[0052] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 20 minutes.

[0053] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 19 minutes.

[0054] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 18 minutes.

[0055] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 17 minutes.

[0056] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 16 minutes.

[0057] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 15 minutes.

[0058] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 14 minutes.

[0059] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 13 minutes.

[0060] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of holding the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 12 minutes.

[0061] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of maintaining the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 11 minutes.

[0062] In an exemplary embodiment, a method for extending the shelf life of packaged food includes the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of maintaining the heated food inside the food packaging at 110-125°C for 10-60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 10 minutes. In one embodiment, in step c), the heated packaged food (food packaging) is cooled using nitrogen gas (N2), cold air, cold water, or ice. Thus, this method may include cooling the heated packaged food (food packaging) using nitrogen gas (N2), cold air, cold water, or ice.

[0063] In this invention, the term "nitrogen gas (N2)" is commonly used as a cooling medium due to its excellent heat transfer properties. Nitrogen gas absorbs thermal energy from food through convection, conduction, and direct contact. This heat exchange rapidly lowers the temperature of the food, promoting efficient and uniform cooling. In some embodiments, the temperature of the nitrogen gas can be in the range of -15 to 10°C, preferably -10 to 5°C, and more preferably -5 to 0°C.

[0064] In this invention, the term "cold air" refers to air that is cooler than the temperature of the food. Cold air is extended to air cooled by various means, such as refrigeration systems, air conditioning systems, and other cooling mechanisms. The temperature range associated with cold air varies depending on the food that needs to be cooled, but it usually means a temperature lower than the food or ambient temperature, or the desired operating temperature. In some embodiments, the temperature of the cold air is in the range of -15°C to 10°C, preferably -10°C to 5°C, and more preferably -5°C to 0°C.

[0065] In this invention, the term "ice" refers to the solid state of water that occurs when water molecules freeze and form a hard crystalline structure. Ice is generally characterized by low temperatures and a distinct solid shape. It is typically formed when the temperature of water reaches or drops below its freezing point, and liquid water transforms into solid ice. In some embodiments, the temperature of ice can be in the range of -15°C to 0°C, preferably -10°C to 0°C, and more preferably -5°C to 0°C.

[0066] In the context of the present invention, the term “ice water” in this patent application refers to a mixture of ice and liquid water. This is produced by combining ice and water, resulting in a solution or mixture containing both solid ice and liquid water phases. Ice water typically has a lower overall temperature than pure liquid water because the presence of ice acts as a coolant.

[0067] In one embodiment, the temperature of the ice water is approximately 0-1°C. In one embodiment, the food is packaged under protective atmospheric pressure, optionally in a nitrogen gas (N2) atmosphere, and the amount of oxygen in the upper space of the food packaging is preferably less than 1 percent. Therefore, in one embodiment, this method includes packaging the food under protective atmospheric pressure, optionally in a nitrogen gas (N2) atmosphere, before step a). When nitrogen gas (N2) is used when packaging the food, the N2 is applied to the surface of the food and is trapped in the upper space between the surface of the food and the lid of the container. Preferably, the N2 is applied before attaching the lid to the container or receiver and closing the packaging.

[0068] In one embodiment, after degassing and before sealing the packaging, the food is placed under vacuum to remove any remaining air and oxygen within the food. Furthermore, after vacuuming the food and before sealing the packaging, there may be a step of introducing N2. The N2 is then captured or trapped in the upper space between the surface of the food and the lid of the container, replacing the air that normally fills the upper space. Preferably, the N2 is applied before sealing the packaging by attaching the lid to the container or receiver.

[0069] In a further embodiment, the present invention relates to packaged foods obtained or obtained by the methods described herein.

[0070] These packaged foods have a long-term refrigerated storage period of at least about 3 months at a storage temperature of about 0 to 12°C, preferably about 0 to 6°C, and more preferably about 0 to 4°C. Preferably, the long-term refrigerated storage period is at least about 6 months, and more preferably at least about 12 months. The present invention makes it possible to extend the refrigerated storage period of food by more than double compared to corresponding products manufactured using standard processing techniques such as pasteurization.

[0071] In certain embodiments, the food is a resealable, refrigerated processed food (REPFED) product.

[0072] In the present invention, the term “food product” refers to food products of plant, animal, or fungal origin intended for consumption as a meal, including, but not limited to, fruits, vegetables, sprouts, fish, meat, eggs, dairy products, cheese, bread, beer, wine, cider, rice, baked goods, edible oils, dips, spreads, pasta, noodles, processed foods, unprocessed foods, high-moisture foods, and REPFED. In certain embodiments, this term does not include low-moisture foods (LMF), which are foods with a water activity lower than the water activity required for microbial growth. LMF is produced by drying or dehydrating foods that are originally low in moisture content, or high-moisture foods (HMF). Typically, the water activity level of LMF is 0.85 or less, including cereals, grains, dried protein products, spices, dried herbs (including tea), nuts, confectionery, snacks, dried fruits, dried vegetables, and seeds.

[0073] As used herein, the term “refrigerated processed foods (REPFED)” is also known as “prepared foods,” “minimally processed refrigerated foods,” “next-generation refrigerated foods,” “chilled foods,” “refrigerated processed foods,” and “vacuum-cooked foods,” and is used in its broadest sense to refer to a diverse group of foods that are stored refrigerated (e.g., in a refrigerator or refrigerated shelf) at a maximum of 12°C, preferably 10°C, and more preferably 4°C.

[0074] In certain embodiments, at temperatures of 0°C to 12°C, preferably 0°C to 10°C, more preferably 0°C to 4°C, the food is free of at least heterotrophic bacteria such as Bacillus cereus, and optionally also free of Listeria monocytogenes, Streptococcus fecal and Clostridium botulinum, and the bacterial spores are at least fatally damaged so that the spores can no longer grow vegetatively in each of the bacteria.

[0075] In certain embodiments, the packaged food is free of heterotrophic Bacillus cereus, and its cryospores are at least fatally damaged. In embodiments, the packaged food is free of heterotrophic Bacillus cereus, and its cryospores are at least fatally damaged, so that the spores can no longer vegetatively grow in the food, which is kept at a maximum of 12°C, preferably a maximum of 10°C, and more preferably a maximum of 4°C. In the present invention, the term "heterotrophic" generally refers to a state in which bacteria are actively growing and multiplying. In this state, bacteria exhibit an active metabolic state and are able to maintain important cellular functions such as nutrient absorption and metabolism.

[0076] As used herein, “vegetative bacteria-free” means that the food is completely free of actively growing and reproducing bacteria, i.e., for practical purposes, the colony-forming units (CFUs) are less than 3.0, preferably less than 2.0, and more preferably less than 1.0 per gram of food. As used herein, “heterotrophic psychrophilic Bacillus cereus-free” means that the food is completely free of actively growing and reproducing psychrophilic Bacillus cereus colony-forming units (CFUs), i.e., less than 3.0, preferably less than 2.0, and more preferably less than 1.0 per gram of food for practical purposes. This means that metabolically active psychrophilic Bacillus cereus, including those involved in important biological processes such as nutrient absorption, metabolism, and growth, are absent or eradicated.

[0077] To test for heterotrophic Bacillus cereus in food, the food is spread on a culture medium to allow any psychrophilic Bacillus cereus present in the food to grow. Typically, psychrophilic Bacillus cereus can be cultured on agar plates and will grow within 4-5 days at 22°C under aerobic conditions. The vegetative bacteria can then be quantified.

[0078] In the context of this patent application, the term “spore” refers to a specific structure formed by certain microorganisms, such as bacteria, as a means of survival and reproduction. These spores are inactive vegetative cells and function as dormant and tolerant forms that enable bacteria to withstand unfavorable environmental conditions such as extreme temperatures, dryness, and exposure to chemicals and radiation. Spores originate from spore-forming bacteria, which can form and release spores during their life cycle. Spores can remain in food even under conditions that inhibit the growth and survival of vegetative bacteria, and under suitable conditions, they can germinate to produce vegetative bacteria.

[0079] To test for the absence of spores in food or for spores that are fatally damaged, the food is added to a culture medium to grow any psychrophilic Bacillus cereus present in the food. Typically, psychrophilic Bacillus cereus spores grow on mannitol egg yolk polymyxin agar and proliferate under aerobic conditions at 30°C for 24–48 hours. If necessary, the food can also be heated at 80°C for 10 minutes before being added to the agar medium to activate the spores. The spores can then be quantified.

[0080] In certain embodiments, the food does not contain preservatives; that is, the manufacturer does not add preservatives to the product from an external source.

[0081] In this specification, the term “preservative” generally refers to chemical substances used to prevent or delay spoilage, such as acids, sorbic acid, sorbates (E200-E203), alcohols, benzoic acid and benzoates (E210-E219), butylhydroxyanisole (BHA), butylhydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), and sulfites (E221-E228). These include nitrites (E249-E250), nitrates (E251-E252), propionates (E281-E283), nisin (E234), natamycin (E235), hexamethylenetetramine (E239), dimethyl decarbonate (E242), ethyl lauroyl alginate (E243), propionic acid (E280), boric acid (E284), sodium tetraborate (E285), and lysozyme (E1105).

[0082] While the present invention has been described in relation to its particular embodiments, it is evident that many substitutions, modifications, and variations are apparent to those skilled in the art in light of the foregoing description. Therefore, it is intended that all such substitutions, modifications, and variations are encompassed within the gist and scope of the appended claims. The aspects and embodiments of the present invention disclosed herein are further supported by the following non-limiting examples. [Examples]

[0083] Example 1 Bacillus cereus strains isolated from REFPED and classified into lineage groups II and VI are particularly selected due to their ability to grow in low-temperature environments (below 10°C). Table 1 provides an overview of the various B. cereus strains described in the literature. The table lists the D of each strain group reported from their respective sources. 90 Or D 95 The values ​​(asterisks) include the minimum, average, and maximum values.

[0084] [Table 1] Table 1. Group II or VI heat-tolerant and psychrophilic B. cereus strains isolated from refrigerated cooked foods.

[0085] Example 2 Based on heat resistance, several strains were selected from the literature. Table 2 shows the D of each strain selected from the literature. 85 , D 90 , and D 95 The values ​​and the ability to grow under low-temperature conditions are displayed. FF140 and FF67 are D 95 As indicated by the values, it has high heat resistance and was identified as a suitable strain. NVH1105-98 shows excellent heat resistance in the literature, however (D 90 (As proven by the values), subsequent tests revealed that the expected heat resistance was insufficient, and as a result, it was excluded from consideration in this invention.

[0086] [Table 2] Table 2. Origin, heat tolerance, and low-temperature characteristics of eight selected B. cereus strains.

[0087] Example 3 Brainheart Infusion (BHI) medium was inoculated with B. cereus spores (104 CFU / g) from strains FF140 and FF67, and different pH values ​​(pH 5.6, 5.8, 6.0) were set. Samples containing B. cereus spores from FF140 and FF67 were placed in metal or stainless steel tubes and stored overnight between 0°C and 2°C to avoid spore germination. The samples were processed according to the method according to a specific embodiment of the present invention. The samples were heated to 105°C or 112°C. After reaching the desired temperature, the temperature of each sample was held at that temperature for 10 or 30 seconds. The samples were then cooled directly to 10°C within 20 minutes using ice or a rapid cooler (Alpeninox, ABP0201), or cooled to 30°C over 2 hours and then cooled to 10°C. For each sample, B. cereus spores were counted at the time of inoculation into BHI and after the method according to a specific embodiment of the present invention. An inoculated, unheated sample was included as a blank at each pH. All analyses were performed twice.

[0088] [Table 3] Table 3 shows the effect of cooling treatment on B. cereus spores inoculated at high concentrations in Brain Heart Infusion (BHI) and the degree of reduction.

[0089] According to the data shown in Table 3, pressurizing and heating samples to 112°C and holding the temperature for 10 or 30 seconds significantly reduced the number of B. cereus vegetative bacteria and spores. Conversely, pressurizing and heating samples to 105°C and holding the temperature for 30 seconds was found to be insufficient to effectively reduce the number of B. cereus vegetative bacteria and spores. In particular, for samples pressurized and heated to 112°C for only a short time (10 seconds), it was found that the length of the cooling period also affected the reduction in the number of vegetative bacteria and B. cereus spores.

[0090] However, the effect of direct cooling to 10°C within 20 minutes, or cooling to 30°C first and then to 10°C, was similar to that of samples pressurized and heated to 112°C in 30 seconds. Furthermore, for samples pressurized and heated to 105°C, direct cooling to 10°C within 20 minutes was found to be more effective in reducing the number of vegetative bacteria and B. cereus spores compared to longer cooling treatments.

[0091] Example 4 Brainheart Infusion (BHI) medium was inoculated with B. cereus spores (104 CFU / g) from strains FF140 and FF67, and different pH values ​​(pH 5.6, 5.8, 6.0) were set. Samples containing B. cereus spores from FF140 and FF67 were placed in metal or stainless steel tubes and stored overnight between 0°C and 2°C to avoid spore germination. The samples were processed according to the method according to a specific embodiment of the present invention. The samples were pressurized and heated to 105°C or 112°C. After reaching the desired temperature, the temperature of each sample was maintained for 10 or 30 seconds. The samples were then cooled to 10°C directly on ice or in a rapid cooler (Alpeninox, ABP0201). The samples were stored at 10°C for 30 and 90 days. After applying the method of the present invention, the number of B. cereus spores was counted for each sample inoculated with BHI after storage at 10°C for 30 days and after storage at 10°C for 90 days.

[0092] [Table 4] Table 4. Number of B. cereus spores in BHI at different time points.

[0093] Based on the data shown in Table 4, samples heat-treated at 105°C and then cooled to 10°C within 20 minutes showed a decrease in the number of B. cereus spores immediately after treatment. Storage of the samples at 10°C for 30 days resulted in a further decrease in spore count. However, after 90 days of storage at 10°C, the number of B. cereus spores increased. This indicates that the spores germinated to become Bacillus cereus vegetative bacteria and were able to produce spores again. In contrast, no increase in spore count was observed after 90 days in samples heated at 112°C for 10 seconds. This indicates that spores damaged during heating could not survive, suffered irreversible (fatal) damage, and eventually died over time. According to a method in a specific embodiment of the present invention, heating the samples at 112°C for 30 seconds reduced the number of B. cereus spores to less than one colony-forming unit (CFU / g). Even after storing these samples at 10°C for 30 or 90 days, the number of B. cereus spores remained below 1 CFU / g. This indicates that the spores were effectively eliminated during treatment and were unable to germinate during storage at 10°C.

[0094] Example 5 To evaluate the effectiveness of the method according to the present invention, the quality and flavor of red cabbage were tested. The red cabbage was treated using three different methods. Method 1 (Method according to the present invention): Red cabbage was pressurized and heated at 112°C for 30 seconds, and then cooled to 10°C within 20 minutes. Method 2: Red cabbage was pasteurized by heating it at 90°C for 10 minutes. Method 3: Red cabbage was sterilized using a general sterilization process, by pressurizing and heating to 121°C for approximately 15 minutes, and then cooling to approximately 40°C within 30 minutes.

[0095] Based on the data shown in Figure 1, it is clear that red cabbage processed by the method of the present invention maintains or only slightly deteriorates in food quality and taste. Red cabbage processed by Method 1 (dark gray) stood out in terms of aroma intensity, aroma freshness, color vibrancy, texture, flavor intensity, and taste freshness compared to cabbage processed by Methods 2 (gray) and 3 (light gray). Furthermore, Figure 1 shows that red cabbage processed by Method 1 has less saltiness, bitterness, and acidity, and is lighter in color. Unlike red cabbage processed by Methods 2 and 3, cabbage processed by Method 1 is not overheated.

Claims

1. A method for extending the shelf life of packaged food, comprising the following steps: a) A process of pressurizing and heating the food inside the food packaging to 110-125°C; b) A step of maintaining the heated food inside the food packaging at 110 to 125°C for 10 to 60 seconds; c) A step of cooling the heated food inside the food packaging to 0-12°C in less than 15 minutes.

2. The method according to claim 1, wherein the food is a refrigerated processed food (REFFED) product that can be stored for a long period of time.

3. The method according to any one of the claims, wherein the pH of the food or at least a portion thereof is at least 4.

6.

4. During at least part of step a) and / or step b), a pressure higher than atmospheric pressure is applied to the outside of the food packaging, preferably 0.1 to 1.0 bar (1 × 10⁻¹⁰) higher than the pressure inside the food packaging. ４ ~1 x 10 ５ Pa), preferably 0.2 to 0.7 bar (2 × 10⁻⁶). ４ ~7 x 10 ４ Pa), for example, 0.1 to 0.3 bar (1 x 10⁻⁶). ４ ~3 x 10 ４ The method according to any of the claims, wherein Pa) is high.

5. The method according to any one of the claims, wherein before step a) and before sealing the packaging, the food is preheated to a temperature of 50°C to 75°C, more preferably 55°C to 70°C, and most preferably 60°C to 65°C under atmospheric pressure.

6. The method according to any of the claims, wherein the food is packaged before step a), and the food is degassed before sealing the packaging, optionally before and / or during preheating.

7. The method according to any one of the claims, wherein a pressure magnetron or an autoclave is used for the pressurized heating and, optionally, for preheating the food.

8. The method according to any one of the claims, wherein the food packaging is immersed in water in order to maintain the heated food inside the food packaging at 110°C to 125°C.

9. In step c), nitrogen gas (N ２ The method according to any one of the claims, wherein the heated food inside the food packaging is cooled using cold air, cold water, or ice.

10. The aforementioned food product is optionally subjected to nitrogen gas (N) under a protective atmosphere. ２ The method according to any one of the claims, wherein the food is packaged under an atmosphere, preferably with an oxygen content of less than 1% in the upper space inside the food packaging.

11. Packaged food that can be manufactured or has been manufactured by the method of any of the above claims.

12. The packaged food according to claim 11, characterized in that the food is a refrigerated processed food (REFFED) product that can be stored for a long period of time.

13. The packaged food according to claim 11 or 12, wherein at a temperature of 0°C to 12°C, the food is free from at least vegetative Bacillus cereus, and optionally free from Listeria monocytogenes and / or Streptococcus fecal and / or Clostridium botulinum, and the spores of the said bacteria are at least fatally damaged so that the spores can no longer grow vegetatively in each of the said bacteria.

14. The packaged food according to any one of claims 11 to 13, characterized in that the packaged food does not contain nutrient-rich psychrophilic Bacillus cereus, and its spores are at least fatally damaged.

15. A packaged food according to any one of claims 11 to 14, which does not contain preservatives.

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