In order to prevent the puffed food from being squeezed and broken, and to prevent the oil from being oxidized and rancid, many puffed food packaging bags should be filled with gas. The data shows that the puffed food packaging should be filled with nitrogen, which is clean, non-toxic and dry, and can guarantee The puffed food will not change color and taste for a long time, and it is safe to eat. Nitrogen is charged in order to inhibit the growth of microorganisms in food (generally, the growth of microorganisms requires oxygen), and the chemical properties of nitrogen are inactive and easy to prepare cheaply. Nitrogen is absolutely non-toxic. The air we breathe is 78% nitrogen and 21% oxygen. Therefore, after filling the gas, the packaging bag will bulge a lot. For the preservative packaging of food, there are preservatives, vacuum packaging, nitrogen-filled protective packaging, etc. For potato chips, nitrogen-filled packaging is more suitable.