Ready-to-eat ham and method of making

Abstract

The present application belongs to the technical field of instant meat product processing, and discloses an instant ham and a preparation method. The method comprises low-salt pickling and semi-mature fermentation, high-temperature three-gradient fermentation after slicing and addition of probiotics, and the combination of vacuum temperature-changing fermentation ripening and bacteriostatic process, and processes the instant ham which is quickly fermented and matured, reduces the content of salt, inhibits the growth of rancidity and harmful bacteria, and is convenient to eat after opening the bag. The present application first proposes that the meat product after rapid fermentation is vacuum packaged and then subjected to special vacuum high-temperature fermentation ripening and bacteriostatic treatment at a high temperature of 49-52 DEG C. The process can not only significantly shorten the fermentation time to about 110-120 minutes, but also basically kill the non-sporulated vegetative microorganism cells in the vacuum-packaged ham, while allowing the probiotics to be retained to a certain extent and avoiding the pollution of microorganisms and other harmful substances thereafter. The "fast, low-salt, flavor, instant" ham product prepared by the present application technology cannot be realized by the existing ham fermentation technology.

Description

Technical Field

[0001] This invention relates to the field of ready-to-eat meat processing technology, specifically to ready-to-eat ham and its preparation method. Background Technology

[0002] Fermented ham is a high-end product among traditional meat products. Famous ham products in my country include Jinhua ham, Xuanwei ham, Rugao ham, and dozens of other regional specialties. Traditional ham has a long history, unique flavor, rich nutrition, and a long shelf life. The traditional processing method uses pork hind legs as raw material. Fresh pork legs are cleaned and thoroughly cured by coating them with salt one to several times. After washing away the salt and impurities, they are hung to air dry before being placed in a fermentation chamber. After a relatively long period of fermentation, maturation, and drying, the finished product is obtained.

[0003] With the improvement of social development and consumption levels, especially the increasing demand for convenient and healthy food, the shortcomings of traditional fermented ham have become increasingly apparent. First, the processing period is long, with a basic fermentation period of at least 6 months, and better fermentation maturity requiring more than a year to ensure the formation of a rich fermented flavor, leading to increased costs and safety risks. Second, to ensure sufficient shelf life and preservation safety and to promote fermentation, a high amount of salt is generally added, sometimes as high as 8% or more, which is increasingly unsuitable for the development of low-salt healthy diets. Third, traditional processes are subject to the natural control of lower temperatures and seasons, and cannot meet the quality requirements of convenient and ready-to-eat products. They are all consumed after heat processing or used as raw materials or ingredients in other dishes.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] To address the problems in the background art, this invention provides a ready-to-eat ham and its preparation method. This ham has a reduced salt content, significantly shortens the fermentation and drying cycle while preserving its flavor, and allows for immediate consumption upon opening the package.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] The pre-treated pork legs are cured with low salt, and after being washed and trimmed, they undergo the first fermentation to the semi-mature stage.

[0008] After the semi-cooked pig leg is skinned and cut into strips, it is inoculated with compound probiotics for a second fermentation.

[0009] The meat strips that have completed the second fermentation are vacuum-packed and then undergo a third fermentation, cooling, and storage.

[0010] The third fermentation is a vacuum high-temperature fermentation for ripening and antibacterial purposes. Specifically, the vacuum-packed meat strips are first fermented at 49-50℃ for 40 minutes, then at 53-55℃ for 30 minutes, and finally at 50-52℃ for 40 minutes. Preferably, the low-salt curing involves using 5-6% of the weight of the pork leg in salt for curing.

[0011] Preferably, the first fermentation to semi-maturation takes 80-90 days at 15-20℃.

[0012] Preferably, the second fermentation is a three-gradient fermentation at a higher temperature after the strips are cut and fermentation bacteria are added, specifically:

[0013] After skinning and slicing semi-cooked pork legs, fermentation bacteria were added for three-gradient fermentation at a relatively high temperature. The fermentation bacteria consisted of *Micrococcus mutans*, *Staphylococcus aureus*, and *Leuconostoc mesenteroides*, mixed in a mass ratio of 1:(1-2):(1-2), with an addition amount of 10g. 6 -10 7 cfu / g pork leg meat;

[0014] The three-gradient fermentation at the higher temperature involves first fermenting at 28-29℃ and 80% relative humidity for 6 hours; then fermenting at 32-34℃ and 75% relative humidity for 6 hours; and finally fermenting at 30-31℃ and 60% relative humidity for 2 hours. Preferably, the amount of the second fermentation adjuvant added is 60-80g / kg of pork leg meat, and the adjuvant contains, by weight, 30-40 parts glucose, 15-20 parts pepper powder, and 10-15 parts chili powder.

[0015] Preferably, the ham is cooled to a core temperature below 14-15°C.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention is the first to propose a special 49-52℃ gradient high-temperature process for vacuum fermentation and ripening of rapidly fermented meat products after vacuum packaging, as well as antibacterial treatment. This process can not only significantly shorten the fermentation time to about 110-120 minutes, but also basically kill the non-spore-forming vegetative microbial cells in vacuum-packaged ham, while allowing probiotics to survive to a certain extent and avoiding subsequent contamination by microorganisms and other harmful substances.

[0018] The first fermentation of this invention uses traditional process conditions, and the second fermentation uses a three-stage gradient fermentation combined with the use of compound probiotics, which can not only improve the flavor of ham, but also inhibit harmful bacteria in ham and delay the rancidity of fatty acids.

[0019] This invention promotes the rapid fermentation and maturation of semi-mature ham by subjecting it to a three-stage secondary fermentation at a high temperature gradient.

[0020] Compared to traditional products, this invention reduces the salt content by more than 40%, effectively solving the problem that the high salt content of traditional ham is detrimental to taste and health. At the same time, it can maintain the good fermentation flavor and safe storage of traditional ham, and has a long shelf life.

[0021] The ham processing cycle of this invention is less than 3 months, while traditional ham processing takes at least 10 months, thus greatly reducing processing energy consumption, saving costs, and promoting the expansion of enterprise processing scale.

[0022] This invention combines semi-mature fermentation, high-temperature three-gradient fermentation with added probiotics, and vacuum variable-temperature fermentation for ripening and antibacterial processes to achieve rapid fermentation and ripening, reduced salt content, inhibition of rancidity and harmful bacteria growth, and convenient ready-to-eat consumption. This is something that existing ham fermentation technologies cannot achieve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0024] The *Micrococcus mutans*, *Staphylococcus aureus*, and *Leuconostoc mellitus* used in the embodiments of this invention were all purchased from Novogene.

[0025] Example 1

[0026] Preparation of ready-to-eat ham:

[0027] 1) After pre-treating the pork hind leg, use a low-salt curing method, applying salt to the ham in several stages. The amount of salt used is 70% of that used in traditional ham (if the original ham weighs 6-8 kg / 100 kg of pork leg, reduce it to 5-6 kg, a reduction of 30%). The curing is done in three stages: first, apply half the amount of salt and cure for 3-4 days; then apply a quarter of the salt and cure for another 3-4 days; finally, apply the remaining salt and cure for another 3-4 days.

[0028] 2) Clean the marinated pork leg, dry the surface moisture, and trim the meat and edges of the pork skin to make it look nice; then ferment it at 18℃ for 82 days until it reaches the semi-mature stage.

[0029] 3) Remove the ham, debone and remove the skin in the cutting area, and cut the ham meat into strips. Add compound probiotics and excipients to the ham strips, and slowly stir to ensure the excipients adhere evenly to the surface of the meat strips. The compound probiotics consist of Microccus Varians, Staphylococcus carnosus, and Leuconostoc carnosus mixed in a 1:1:1 mass ratio, and the amount added is 10g. 6 -10 7 cfu / g meat; auxiliary ingredients are 60-80g / kg meat, and the auxiliary ingredients are 30 parts glucose, 20 parts pepper powder, and 10 parts chili powder by weight.

[0030] 4) The ham strips are fermented using a higher temperature gradient, raising the traditional fermentation temperature of 15-20℃ to above 28℃ and making gradient changes. Specifically, first ferment at 28-29℃ and 80% relative humidity for 6 hours; then at 32-34℃ and 75% relative humidity for 6 hours; and finally at 30-31℃ and 60% relative humidity for 2 hours.

[0031] 5) Packaging, high-temperature ripening, and antibacterial treatment:

[0032] After the meat strips fermented in step 4) are cooled to room temperature, they are vacuum-packed and then fermented and ripened under vacuum conditions to inhibit harmful bacteria. Specifically, the fermentation process is carried out at high temperature: 49-50℃ for 40 minutes; 53-55℃ for 30 minutes; and 50-52℃ for 40 minutes.

[0033] 6) After the heat-treated ham strips have cooled to a core temperature below 14-15℃, store them at a constant temperature.

[0034] Experimental Example 1

[0035] To investigate the effects of compound probiotics and high-temperature fermentation on the present invention, the ready-to-eat ham prepared in Example 1 was used as the experimental group for performance testing, and the following control groups were set up: Control group 1, where the compound probiotics were replaced with an equal amount of Micrococcus variants; Control group 2, where the compound probiotics were replaced with an equal amount of Staphylococcus aureus; Control group 3, where the compound probiotics were replaced with an equal amount of Leuconostoc mesenteroides; Control group 4, where the compound probiotics were replaced with an equal amount of the commonly used lactic acid bacteria Lactobacillus plantarum; Control group 5, where the addition of compound probiotics was not performed.

[0036] The specific performance tests and methods are as follows:

[0037] Total bacterial count determination: GB 4789.2-2022 "National Food Safety Standard - Microbiological Examination of Food - Determination of Total Bacterial Count";

[0038] Listeria monocytogenes test: GB 4789.30-2016 "National Food Safety Standard for Microbiological Examination of Food: Test for Listeria monocytogenes";

[0039] Enteric flora determination: GB 4789.3-2016 "National Food Safety Standard for Microbiological Examination of Food - Coliform Count";

[0040] Salmonella testing: GB 4789.4-2024 "National Food Safety Standard - Microbiological Examination of Food - Salmonella Testing";

[0041] Shigella testing: GB 4789.5-2012 "National Food Safety Standard - Microbiological Examination of Food - Shigella Testing";

[0042] Staphylococcus aureus testing: GB 4789.10-2016 National Food Safety Standard - Microbiological Examination of Food - Staphylococcus aureus testing;

[0043] Test for diarrhea-causing Escherichia coli: GB / T 4789.6-2003 "Food Hygiene Microbiology Examination: Test for Diarrhea-causing Escherichia coli";

[0044] Test for Vibrio parahaemolyticus: GB / T 4789.7-2008 "Food Hygiene Microbiological Examination: Test for Vibrio parahaemolyticus";

[0045] Test for Yersinia enterocolitica (GB / T 4789.8-2008) – Food Hygiene Microbiology Examination: Test for Yersinia enterocolitica.

[0046] Campylobacter jejuni test: GB / T 4789.9 "Food Hygiene Microbiology Examination: Campylobacter jejuni Test";

[0047] Hemolytic streptococci test: GB / T47 89.11 "Food Hygiene Microbiological Examination: Hemolytic Streptococci Test";

[0048] Micrococcus assay: Plate culture method using micrococcus-specific culture medium;

[0049] Staphylococcus assay: Plate culture method on staphylococcus-specific culture medium;

[0050] Sensory index determination: Sensory analysis - Guidelines for sensory quality control of food GB / T29605-2013;

[0051] Determination of free amino acids: GB5009.124-2016 "National Food Safety Standard - Determination of Amino Acids in Food";

[0052] Determination of volatile fatty acids: GB5009.168-2016 National Food Safety Standard - Determination of fatty acids in food (gas chromatography).

[0053] Peroxide value determination: GB5009.179-2016 "National Food Safety Standard - Determination of Peroxide Value in Food";

[0054] Texture testing: The hardness, elasticity, and chewiness of the product are measured using a texture analyzer;

[0055] water activity a w Measurement: GB 5009.238-2016 "National Food Safety Standard - Determination of Water Activity in Food";

[0056] Moisture determination: GB 5009.3-2010 "National Food Safety Standard - Determination of Moisture in Food";

[0057] Shelf life: Determined according to the National Food Safety Standard for Cured Meat Products (GB 2730-2015), based on sensory evaluation, peroxide value determination, pathogenic bacteria determination, etc.

[0058] The measurement results are shown in Table 1.

[0059] Table 1 Performance test results of experimental and control groups

[0060] .

[0061] As shown in Table 1, under the high-temperature fermentation conditions of this experiment, *Micrococcus* exhibited a strong ability to decompose carbohydrates, breaking down various types of carbohydrates and providing a unique flavor to the dried cured meat. *Staphylococcus aureus*, on the other hand, primarily targets meat protein, breaking it down into amino acids and polypeptides, and fats into secondary fatty acids. Furthermore, *Staphylococcus aureus* and *Leuconostoc mesenteroides* can inhibit the growth of *Listeria monocytogenes* and other harmful bacteria that are most likely to remain and multiply in ham. They can also inhibit the growth of other miscellaneous bacteria through nutrient and spatial competition, delaying rancidity. Through synergistic effects, they achieve antibacterial and preservative effects, and enhance the flavor of ham by increasing the amino acids and fatty acids in the ham.

[0062] Table 1 shows that the *Micrococcus mutans*, *Staphylococcus aureus*, and *Leuconostoc mesenteroides* used in this invention, under higher fermentation conditions, exhibit superior individual or synergistic effects compared to previously reported probiotics such as lactic acid bacteria. The ham quality achieved is close to or even superior to products fermented using traditional long-term methods. The compound bacteria used in this application demonstrate even better synergistic effects, significantly outperforming single-strain and traditionally long-term fermented hams in improving product flavor, enhancing quality, and providing antibacterial and preservative properties.

[0063] Experimental Example 2

[0064] To investigate the impact of fermentation process on the present invention, the ready-to-eat ham prepared in Example 1 was used as the experimental group for performance testing, and the following control group was set up: the traditional process is room temperature fermentation. Compared with Example 1, the only difference is that the temperature of the second and third fermentations is 15-20℃, that is, direct post-fermentation maturation. The determination method in Experiment 1 was used, and the results are shown in Table 2.

[0065] Table 2 Performance test results of experimental and control groups

[0066] .

[0067] As shown in Table 2, compared with the traditional process, the product characteristic indicators did not show significant differences after the first stage of fermentation. The most significant differences, however, appeared after the high-temperature rapid fermentation in the second stage of this embodiment, and the significant differences continued to emerge after the high-temperature maturation and antibacterial treatment in the third stage. The main difference in indicators is that the product of this invention exhibits better sensory characteristics after high-temperature rapid fermentation, with flavor compounds (free fatty acids and amino acids) increasing by more than 20%, probiotics increasing by more than 3 times, and peroxide value decreasing by 4 times.

[0068] Experimental Example 3

[0069] The ready-to-eat ham prepared in Example 1 and traditional ham products were subjected to sensory, physicochemical, and microbiological tests to compare their effects on product characteristics. The results are shown in Table 3. The indicators for traditional ham products were referenced from the product indicators in "Physicochemical and Flavor Properties of Nuodeng Ham from Different Sources and Years, Liu Biqin et al., Meat Research".

[0070] Table 3 Comparison of characteristics between Example 1 product and traditional product

[0071] .

[0072] Table 3 shows that the ready-to-eat ham of the present invention has significantly higher levels of sensory evaluation, free amino acids and fatty acids, moisture content, shelf life, and probiotics, while its salt content, peroxide value, and water activity are significantly lower, and its shelf life is the same, with a shorter production cycle.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing ready-to-eat ham, characterized in that, Include: The pre-treated pork legs are cured with low salt, then washed, trimmed, and fermented at 15-20℃ for 80-90 days. After the semi-cooked pig leg is skinned and cut into strips, it is inoculated with compound probiotics for a second fermentation. The meat strips that have completed the second fermentation are vacuum-packed and then undergo a third fermentation, cooling, and storage. The third fermentation is vacuum high-temperature fermentation for ripening and antibacterial purposes. Specifically, the vacuum-packed meat strips are first fermented at 49-50℃ for 40 minutes, then at 53-55℃ for 30 minutes, and finally at 50-52℃ for 40 minutes. The second fermentation is a three-gradient fermentation at a higher temperature after the strips are cut and fermentation bacteria are added, specifically: After the semi-cooked pig leg is skinned and cut into strips, fermentation bacteria are added for three-gradient fermentation at a higher temperature. The fermentation bacteria are Micrococcus mutans, Staphylococcus aureus, and Leuconostoc mesenteroides, mixed in a mass ratio of 1:(1-2):(1-2) to obtain a compound probiotic, and the addition amount is 10. 6 -10 7 cfu / g pork leg meat; The three-gradient fermentation at the higher temperature involves first fermenting at 28-29℃ and 80% relative humidity for 6 hours; then fermenting at 32-34℃ and 75% relative humidity for 6 hours; and finally fermenting at 30-31℃ and 60% relative humidity for 2 hours.

2. The preparation method according to claim 1, characterized in that, The low-salt curing process involves using 5-6% of the weight of the pork leg in salt for curing.

3. The preparation method according to claim 1, characterized in that, After the semi-cooked pork leg is skinned and cut into strips, it is fermented again with the addition of auxiliary ingredients. The amount of the auxiliary ingredients added is 60-80g / kg of pork leg meat. The auxiliary ingredients contain 30-40 parts glucose, 15-20 parts pepper powder and 10-15 parts chili powder by weight.

4. The preparation method according to claim 1, characterized in that, The cooling process involves cooling the core temperature to below 14°C.

5. Ready-to-eat ham obtained by the preparation method according to any one of claims 1-4.