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Vacuum bag is divided into transparent vacuum bag and aluminum foil vacuum bag, the composite material of the vacuum bag is PE plus nylon composite, nylon has good barrier performance, can effectively prevent moisture and gas, can keep the vacuum state for a long time, and ordinary plastic bags are just ordinary plastic, such plastic bags have holes on the surface, can not be vacuum-packed, even if barely packed, It will leak over time, even as soon as it is packed.

If you want to maintain the freshness of food for a long time, it can not be achieved by vacuuming, because when the oxygen concentration in the bag is less than 1%, the growth and reproduction rate of microorganisms will drop sharply, when the oxygen concentration is less than 0.5%, most microorganisms will be inhibited and stop reproduction, and vacuum packaging can not inhibit the reproduction and enzyme reaction caused by food deterioration and discoloration. Therefore, it also needs to be combined with other auxiliary methods, such as refrigeration, freezing, dehydration, salt pickling and so on.