Some can't be vacuumed, so the food inside is easily crushed. Sometimes it is necessary to inflate the packaging bag to prevent the food from being crushed. Deoxidizer is used to protect foods with high oil content from the smell of oil oxidation. Desiccant is used to prevent food from getting wet. If we want to improve the shelf life, the key problem is the cooperation of preservatives, and this measure on packaging alone is still far from enough.