First of all, the main purpose of vacuum pumping in the design of food packaging bag is to prevent the contact between air and food, slow down food oxidation, so as to avoid microbial growth and food deterioration. Whether to vacuum or not depends on the characteristics of food and the length of anti-corrosion time. Generally, the food that can be sold in a short time and should not be added with too many preservatives, such as cooked chicken feet and pig feet, and the packaging of some cereals is more suitable for vacuum pumping.

抽真空的食品包装特别要注意的是抽真空并不能阻断食物里面的细菌生长，只能对那些需要氧气的微生物减缓的作用，要想食物不腐坏，延长保质期，就需要对食物进行处理，比如说使用高温，紫外线灯光照射等等方式，然后在使用锅的食品包装袋进行包装抽真空，这样就大大的延长了保质期。

Special attention should be paid to the food packaging of vacuum pumping. Vacuum pumping can not block the growth of bacteria in the food, but can only slow down the microorganisms that need oxygen. In order to prevent food from spoilage and prolong the shelf life, it is necessary to sterilize the food, such as high temperature, ultraviolet light irradiation and so on, Then vacuum the food packaging bag using the sterilizer, which greatly prolongs the shelf life.

另外我们在当中看到的一些包装袋是鼓鼓的里面有气体，这是另外一种防腐手段，采用的是给包装袋冲入一些惰性气体，例如常用的氮气，二氧化碳等单一或者组合气体，这种成本也比较低，多使用在膨化食品包装当中，保持食品干燥，防止食物变质。

In addition, some of the packaging bags we see in the supermarket are bulging with gas inside. This is another anti-corrosion method. It uses to inject some inert gases into the packaging bags, such as common single or combined gases such as nitrogen and carbon dioxide. This kind of cost is also relatively low. It is mostly used in puffed food packaging to keep the food dry and prevent food deterioration.