Fresh meat packaging technology for cooling meat

【Chinese Packaging Network News】Cooled meat refers to the strict implementation of the quarantine system after the slaughter of livestock and poultry carcasses quickly processed, so that carcass temperature (the later leg as a measurement point) within 24h to 0 degrees -4 degrees, and in the follow-up During the processing, distribution, and retail processes, fresh meat is kept within the range of 0 degrees to 4 degrees. Since the cooled meat is always under cooling conditions and undergoes a full after-ripening process, the cooled meat is characterized by less juice loss, soft texture and elasticity, delicious taste, and high nutritional value compared to hot and frozen meat. Consumers are welcome. The developed countries began production and promotion in the 20th and 30th centuries. At present, more than 90% of raw meat consumed is cooled meat. China's meat will be an inevitable trend of the development of fresh meat. Extending the retention period of the cooling meat is very important for the development of cooling meat.

The main cause of spoilage of meat is the propagation of microorganisms, the action of enzymes and oxidation. In theory, the storage of meat is slaughter and processing, using good hygiene practices to prevent microbial contamination as much as possible. Use appropriate methods of preservation and preservation to prevent or delay the process of these effects.

Packaging technology is widely used in the preservation of fresh meat. The main functions of packaging are: inhibiting the growth of microorganisms; preventing secondary pollution; slowing down the rate of fat oxidation; making meat products tidy and improving their competitiveness.

First, vacuum packaging (VP). Vacuum packaging reduces the oxygen content by drawing out the air inside the package. Maintains the lavender in the reduced state of myoglobin in meat, but when the meat comes out of the bag, it can quickly restore the bright red; the yin and stop meat contact with the outside world to create pollution, so that the product and the outside world are guaranteed The high-negative diaphragm prevents weight loss due to dehydration on the meat surface; it inhibits the growth and reproduction of aerobic bacteria and relatively prolongs the shelf life of the meat. There are three types of domestic fresh meat packaging, with a shelf life of up to 21 days; (1) Segmented beef and pork pieces are packaged in shrink-wrapped bags, then vacuum- and heat-sealable, and hot water is used to shrink the bags; (2) Adopt thermoforming vacuum packaging machine and high barrier plastic film packaging. A single piece of beef or pork is put into a thermoformed plastic box and then vacuum-sealed with a cover film. (3) The vacuum body packaging is widely used in Europe. Currently, there are studies in China that combine the use of vacuum packaging with brighteners. Make full use of their respective advantages, have a good effect of preservation.

Second, modified atmosphere packaging (MAP or CAP). In modified atmosphere packaging, fresh meat is placed in the packaging, air is drawn off, and the gas environment is replaced with a selected gas to inhibit the growth of microorganisms, thereby prolonging the shelf life of fresh meat. The commonly used gases for modified atmosphere packaging are: (1) The growth of CO2 bacteria and fungi, especially in the early stages of bacterial growth, can also inhibit the activity of enzymes, and fungi, such as mold, and bacillus and achromobacter, are highly sensitive to CO2. When it was inhibited, CO2 had little inhibition on yeasts, and there was no inhibitory effect on lactic acid bacteria until anaerobic bacteria. Studies have shown that the use of 100% CO2 modified atmosphere packaging lambs, there is a significant effect of extended storage period, a significant inhibition of pseudomonads, and lactic acid bacteria become an advantage. (2) The role of CO2 is to maintain oxymyoglobin, which makes the flesh color bright, but it also creates a good environment for many harmful bacteria; (3) N2 is an inert filling table inflatable body, does not sound the color of meat, can prevent oxidation The rancidity, growth of mold, and parasites prevent collapse of the package caused by the large amount of CO2 dissolved in the meat.

In the meat preservation, the ratio of the devil-mixed gas in the world is different. The preservation effect is not the same, usually divided into high oxygen packaging and low oxygen packaging. High-oxygen tone packaging can maintain a good red color. In a high-oxygen-adjusted package, aerobic bacteria can be slowly propagated when the concentration of CO2 is less than 20%. When the concentration of CO2 exceeds 20%, bacterial growth can be halved. However, when the concentration of CO2 is higher than 25%, the water-soluble protein precipitates, making the meat a comprehensive color. Therefore, the CO2 concentration in the high-oxygen-adjusted packaging is generally between 20% and 25%, and the O2 concentration is greater than 60%. For N2; the purpose of low-oxygen tone packaging is to play a CO2 inhibitory effect, but can not maintain the color of flat meat, low-oxygen-adjustable packaging mixture gas range is relatively wide, CO2 is in the range of 50% -90%, N2 in the range of From 10% to 40%, the proportion of O2 is between 1% and 10%. High-oxygen tone packaging is used for small retail packaging, while low oxygen packaging is used for large packages of fresh meat. Under the cooling condition of 0°C-4°C, the pork was preserved in air, vacuum, and modified atmosphere. The results showed that: O220%, CO230%, and O250%, CO250% modified pork packaging has better preservation effect than vacuum. Packaging and air packaging are good, and the shelf life can be extended by 6 days.

Studies have shown that the addition of CO to modified atmosphere packaging makes use of CO and myoglobin to form a more stable carbon monoxide myoglobin (MbCO) than oxymyoglobin (MbO2), while the cooled meat has a bright red color. Studies abroad have shown that: The preservation effect of modified atmosphere packaging with 1% CO is superior to vacuum and other high-gas packaging without CO. Domestic experts have studied cooling pork in different packaging forms. The experimental results show that the CO-containing group is an ideal method for the preservation of fresh meat. In the 21-day storage process, not only the TVB and TBA values ​​are low. , Red stable, and no odor, can inhibit the growth of spoilage bacteria, in addition to weak inhibition of lactic acid bacteria, the Pseudomonas, Chlamydia bacillus, and heat-killed fungus have a strong inhibitory effect, which The effect on spoilage bacteria was significantly better than that of the vacuum packaging group and the oxygen-containing packaging group.

With the cooling meat becoming the mainstream of meat consumption, packaging and sales of cooled meat is an imperative trend. Reasonable and effective packaging will be more and more widely used in the production and distribution of cooled meat. development of.

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