Nitrogen has a special effect in food packaging: it does not chemically react with food and is not absorbed by food, can reduce the oxygen and water content in the packaging, greatly inhibit the growth and reproduction of bacteria, molds and other microorganisms, and slow down the oxidative deterioration of food And decay, so that the food is kept fresh. Nitrogen-filled packaged food can also prevent the food from crushing, sticking or shrinking, maintaining the geometric shape, dryness, crispness, color, and flavor of the food. At present, nitrogen-filled packaging is rapidly replacing traditional vacuum packaging, and has been used in meat products, fruit and vegetable chips, fried potato chips and French fries, oil cooking and other food industries.