Also known as decompression packaging, all the air in the packaging container is pumped out and sealed, so that the bag is in a highly decompressed state. The lack of air is equivalent to the lack of oxygen, which makes microorganisms have no living conditions, so as to achieve the purpose of fresh fruit without disease and rot.

Applications include vacuum packaging of plastic bags, aluminum foil packaging, glassware, plastics and their composite packaging. Packaging materials can be selected according to the types of articles. Because fruit is fresh food and still breathing, high hypoxia can cause physiological diseases. Therefore, less fruits are packed in vacuum.

Vacuum packaging can protect products from environmental pollution, extend the shelf life of food and improve the value and quality of products. Vacuum packaging technology originated in the 1940s. Since 1950, polyester and polyethylene plastic films were successfully applied to commodity packaging, vacuum packaging machines have developed rapidly.

In people's life and work fields, all kinds of plastic vacuum packaging abound. Portable, sealed, fresh-keeping, anticorrosive and antirust plastic vacuum packaging covers many fields, from food to medicines and knitwear, from precision product manufacturing to metal processing plants and laboratories. The increasingly extensive application of plastic vacuum packaging promotes the development of plastic vacuum packaging machine, and puts forward higher requirements for it.

Mechanism of vacuum packaging: Its purpose is to reduce the oxygen content in the package, prevent the packaged food from mildew and deterioration, maintain the color and flavor of the food, and extend the shelf life.

The main function of vacuum packaging is to remove oxygen, thus preventing food from spoilage. Its principle is also relatively simple, because food mildew and corruption are mainly caused by microbial activities, and most microorganisms (such as mold and yeast) need oxygen to survive. Vacuum packaging is to use this principle to pump oxygen out of packaging bags and food cells, so that tiny objects lose their "living environment".

Experiments show that when the oxygen concentration in the packaging bag is ≤ 65438 0%, the growth and reproduction speed of microorganisms will drop sharply, and when the oxygen concentration is ≤0.5%, most microorganisms will be inhibited and stop reproducing. (Note: Vacuum packaging can't inhibit food deterioration and discoloration caused by anaerobic bacteria reproduction and enzyme reaction, and it needs to be combined with other auxiliary methods, such as cold storage, quick freezing, dehydration, high-temperature sterilization, irradiation sterilization, microwave sterilization, salt curing, etc. )