Food safety has always been a major national concern for people's livelihood, which is related to people's daily life safety. In the booming economy of China, the food safety problem is becoming more and more serious. There are many safety problems such as gutter oil and toxic oil layer, which should be paid attention to immediately. The state stipulates that the following five kinds of food shall be destroyed. The five categories of food shall be withdrawn from the market by measures such as stopping the operation, taking off the shelves for storage, destroying and returning to the food producers: 1. Foods that have caused food pollution, food borne diseases or harm or even death to human health; 2. Food that may cause food pollution, food borne diseases or harm to human health; 3. Foods that contain ingredients that may cause health hazards to specific populations but are not marked on food labels and instructions, or are not completely or clearly marked; 4. Foods beyond the shelf life; 5. Other foods that do not meet the food safety standards or requirements. Food safety refers to the non-toxic and harmless food, which meets the necessary nutritional requirements and does not cause any acute, sub acute or chronic harm to human health. According to the definition of Beinuo food safety, food safety is "the public health problem of the impact of toxic and harmful substances in food on human health". Food safety is also an interdisciplinary field that specially discusses how to ensure food hygiene and food safety, reduce disease potential and prevent food poisoning in the process of food processing, storage and sales, so food safety is very important.