Vacuum packaging is a packaging technology widely used in food, electronic products and many other fields. It plays a key role in the preservation and transportation of products.

Basic Principles

Principle of air pressure difference

The core of vacuum packaging is to create and use the pressure difference. Under normal circumstances, the air pressure inside and outside the package is the same. The vacuum packaging equipment uses a vacuum pump to extract the air inside the package, making the air pressure inside the package much lower than the external atmospheric pressure. Generally speaking, the vacuum degree in the package can reach a certain negative pressure level, such as-0.08MPa to-0.1MPa. When the set vacuum degree is reached, the packaging equipment quickly seals the packaging bag, so that under the action of the external atmospheric pressure, the packaging bag will be tightly attached to the surface of the product.

Principle of inhibiting oxidation and microbial growth

The deterioration of many products is caused by oxidation reaction and the growth and reproduction of microorganisms. For food, the oxygen in the air will oxidize with the ingredients in the food (such as oil, vitamins, etc.). For example, when oxygen comes into contact with fats and oils in food, it will cause oxidative rancidity of the fats and oils, producing odors and harmful substances. Through vacuum packaging, the oxygen content is greatly reduced, and the oxygen concentration in the package can generally be controlled at a very low level, such as below 1%, thereby effectively delaying the oxidation process.

At the same time, the growth and reproduction of microorganisms (such as bacteria, mold and yeast) usually need oxygen. In a vacuum environment, the growth of aerobic microorganisms is greatly inhibited. For some products that are susceptible to microbial contamination, such as meat and dairy products, vacuum packaging can significantly extend their shelf life. For example, at the right temperature, ordinary meat may only be stored for a few days under non-vacuum packaging, while it can be stored for several weeks after vacuum packaging.