Application of the hottest high-tech in meat proce

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Application of high and new technology in meat processing and packaging (II)

2.3.1 modified atmosphere packaging technology

the preservation mechanism of modified atmosphere packaging is: by filling a certain component of gas into the packaging, to destroy or change the gas conditions under which microorganisms rely on survival and reproduction, so as to slow down the biochemical change of packaged food and achieve the purpose of preservation and corrosion prevention. The gas used for modified atmosphere packaging is usually CO2, O2, N2 or a combination of them in different proportions. CO2 is a biological inhibitor in modified atmosphere packaging, and can reduce the pH value of meat, but has no effect on anaerobic bacteria and yeast. Carbon dioxide has high permeability to plastic packaging film, which is easy to collapse the packaging. Oxygen can inhibit the growth of anaerobic bacteria and make the meat bright red in a short time, but it can greatly shorten the storage period. Nitrogen has a very low permeability and is an inert gas, which can be used as a buffer or stable gas for mixed gas to prevent the collapse caused by the escape of carbon dioxide

modified atmosphere packaging technology for fresh meat: (1) 100% pure carbon dioxide modified atmosphere packaging can greatly improve the storage life of fresh meat after being filled with oxygen free carbon dioxide at 0 ℃ to the degree of saturation. At the same time, it can prevent oxidative browning of meat color caused by low oxygen partial pressure. In order to make the meat bright red, change the oxygen-containing packaging or use polystyrene tray covered with polyethylene film before retail sale, Make oxygen contact with meat to form bright red oxygenated myoglobin (change to retail packaged fresh meat 0 ℃, 7D). (2) 75% oxygen and 25% carbon dioxide. When the mixed gas is filled into the fresh meat package, the oxygenated myoglobin can be produced, and the meat can be preserved in a short time. (it can be stored for 10 ~ 14d at 0 ℃) (3) 50% oxygen, 25% carbon dioxide and 25% nitrogen can not only make the meat bright red, but also prevent collapse due to the escape of carbon dioxide. (stored at 0 ℃ for 14d) the experiment shows that 100% carbon dioxide has the worst corrosion prevention effect and the shortest shelf life

the fresh-keeping effect of modified atmosphere packaging of fresh meat depends on: (1) the hygienic index of fresh meat before packaging; (2) the barrier property and sealing quality of packaging materials; (3) whether the gas ratio used meets the fresh-keeping requirements; (4) the storage environment temperature of packaged meat

2.3.2 active packaging technology

active packaging refers to the packaging that packaging researchers are turning to graphene to develop solutions, which can not only package food, but also play a certain beneficial role. There are the following kinds: (1) sealing the deoxidizer package can reduce the oxygen concentration in the package to 0.01%. There are two deoxidizers suitable for meat products, such as reduced iron powder and ferrous salts. The other is based on organic matrix, such as enzymes, ascorbic acid, etc. Sealing deoxidizer is often used in combination with vacuum or inflatable packaging, and is widely used. (2) Sealed in CO2 generator package. Controlling the amount of carbon dioxide is a supplement to controlling oxygen. High carbon dioxide concentration (10% ~ 80%) is particularly important for the storage of meat and poultry products, but the permeability of carbon dioxide to plastic film is 5 ~ 10 times that of oxygen. Therefore, carbon dioxide generating agent is required. The small package containing carbon dioxide can be used for the packaging of newly processed meat products to prolong the service life by 3 times. (3) Seal in antimicrobial package. Meat products have the possibility of secondary contamination by bacteria in the process of storage, transportation and sales. Therefore, films or small packages that can release antibacterial agents are popular internationally to inhibit the growth and reproduction of harmful bacteria

there are few examples of active packaging used in meat products in China, but with the unremitting efforts of food science and technology personnel, meat products with active packaging will appear in front of consumers with a new attitude

2.3.3application of nisin biological preservation technology

biological preservation refers to the use of lactic acid bacteria as a protective strain to inhibit spoilage and pathogenic bacteria in food. Some lactic acid bacteria can secrete a class of peptides with strong antibacterial activity. In 1947, mattickatr et al. Prepared this polypeptide from the fermentation broth of Streptococcus lactis and named it nisin. In 1951, hisrsh first used nisin for food preservation and successfully inhibited the swelling and corruption of Ehrlich cheese caused by Clostridium botulinum. Since then, it has been widely used in the food industry. Nisin has been used in meat products abroad for a long time, but the application of nisin in meat products in China is limited to the research stage. Kongbaohua (1997) added nisin to red sausage to significantly reduce the total number of bacteria. Yuanqiuping's research showed that when nisin was added to sausage at 0.3gkg, most Gram-positive bacteria were inhibited, and the color, aroma and taste of the product were not affected. Luo Xin et al. Showed that nisin had obvious antibacterial effect on the preservation of chilled beef meat, and the preservation effect increased with the increase of concentration. Sunjingxin et al. (1994) reported that nisin and sodium lactate alone can prolong the shelf life of products, but if they are used together, the shelf life will be longer and the use of nitrite will be reduced

nisin is a narrow-spectrum antibiotic, which can only kill and inhibit g+ bacteria and has no effect on g-, yeast and mold. Therefore, nisin is usually used in combination with several other sterilization or antibacterial methods. (1) Nisin is combined with heat treatment. Adding a small amount of nisin can greatly reduce the sterilization temperature and time, and improve the thermal sensitivity of hydraulic spoilage microorganisms in the universal material testing machine and pressure testing machine used in most construction engineering laboratories in Anhui Province, so as to prolong the shelf life of meat products. (2) Nisin is used in combination with sorbic acid and other chemical preservatives. Sorbic acid mainly inhibits mold and yeast. (3) Nisin, combined with radiation, ultraviolet, microwave and other sterilization methods, can enhance the sterilization effect

the application of nisin is limited due to the high cost of biological agents and the need for nisin strains to be heated after heat treatment. However, we believe that with the development of biotechnology, nisin will play a great role in the storage and preservation of meat products

2.3.4 application of radiation preservation technology

the radiation of meat is to use atomic energy ray energy for sterilization, which is a cold processing method. The meat will not rise internally. (1) pressure adaptive oil source temperature is adopted, which will not cause changes in the color, aroma and taste of food. Therefore, it can minimize the loss of flavor and taste of meat, prevent the corruption of meat, and achieve the purpose of extending the shelf life. Due to the above physical treatment methods, no chemical residues will be left in the meat at low doses, and the energy consumption is also very low, which greatly reduces the production cost, so it is beneficial to the industry and consumers

fda agrees to apply irradiation technology to fresh meat and meat products. At present, irradiation treated packaged fresh meat and meat products can be seen on supermarkets in the United States. The packages of these meat products are labeled with "green food". According to the strength and durability of FRP, the preservation period of packaged meat irradiated by electron beam at 4 ℃ can be increased from 40d to 90d

(to be continued)

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