In recent years, the sales mode of pork have gradually changed from traditional way to meat cutting. With the market promotion, some problems have been exposed, among which the most prominent one is the short shelf life of the product. Reasons may be: Most slaughtering and segmentation enterprises have shortcomings in management, such as unsatisfactory workshop environment, inadequate cold chain control, resulting in unstable product quality, and usually only 2-4 days shelf life.The main factors that affecting the sales period of fresh pork are the microbial contamination during processing, circulation and storage, product exposure and temperature fluctuation.
With higher requirements on the quality of fresh pork, the exposed products will be gradually replaced by packaged ones, which can inhibit the growth of microorganisms, prevent secondary pollution in the circulation process, slow down the rate of oxidation, improve the appearance quality of products, so as to extend the product sales period and improve the overall competitiveness.
The common packaging methods of chilled meat: tray packaging, vacuum packaging and MAP packaging. Tray packaging uses food-grade tray and seal with self-adhesive film, which has the advantages of simple operation, low cost, strong practicality and so on. It is widely used in large supermarkets, but shelf life is just 3 to 4 days. Therefore, the main ways to divide chilled meat are vacuum packaging and MAP packaging.
Vacuum packing is the most common way for large packing. The working principle is to eliminate the air to slows down the microbial growth and spoilage, so as to extend the shelf life of products. However this packaging way also has quality defects such as deformation, the juice loss and dim colour. Vacuum heat shrinkable packaging can guarantee about 15 to 20 days shelf life. The vacuum-shrinkable packaging not only reduced the microbial growth speed, but also extended the shelf life of the product, greatly reduced the transportation and marketing cost, meanwhile obviously improved the meat color.
Generally MAP packaging adopts the combination of carbon dioxide, nitrogen and oxygen. MAP packaging extend products shelf life by changing or destorying the tray inner environment/microbial living conditions. Compared with vacuum packaging, MAPpackaging can reduce juice loss, maintain product color and so on, and is suitable for small retail packaging. At present, the shelf life of can be 7 to 10 days.