Fresh-keeping bags mainly refer to bags made of food-preserving film that are mainly used for storing vegetables, fruits, cereals, cooked food and other foods, and are widely used in daily life. The fresh-keeping bags are divided into polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC) and other types according to the production materials.
PE and PVDC fresh-keeping bags are relatively safe. PE is mainly used for packaging of fruits and vegetables. PVDC is mainly used for packaging of cooked food and ham. Although PVC fresh-keeping bags are widely used in the outer packaging of food and vegetables, they have certain potential harm to human body. The harm mainly comes from two aspects: one is the residual amount of vinyl chloride monomer in the product (the safety limit standard of vinyl chloride on the human body is less than 1mg / kg), and the other is the type and content of processing aids used in the process. There are two substances in PVC that have the potential to cause cancer, one is VCM (vinyl chloride monomer) and one is DEHA (plasticizer), if the composition of VCM is non-toxic in the range of 1PPM (parts per million) If it exceeds the standard, there is the possibility of carcinogenicity; and the plasticizer will be released at high temperature and harmful to the human body. Therefore, the General Administration of Quality Supervision, Inspection and Quarantine in 2005 strictly prohibits the use of plasticizers by companies that produce PVC, and prohibits the use of PVC plastic bags to package meat, cooked food, tofu and other foods that can be eaten directly.
Pay attention to the following points when choosing fresh-keeping bags:
1. Pay attention to the material marked on the product: Polyethylene bags (PE) are widely used for food packaging; polypropylene bags (PP) have high transparency, mainly used for the packaging of bread and snacks; polyvinyl chloride bags (PVC) can also be used It is used for the packaging of perishable foods such as vegetables and fruits, but it cannot be used for the packaging of oily foods, nor can it be used for heating in microwave ovens.
2. When heating food in a microwave oven, use a fresh-keeping bag (such as Miaojie and Xubaoxian) with "special microwave oven".
3. The cold storage and frozen food in the refrigerator should use fresh-keeping bags instead of ordinary plastic bags. The special process and raw materials of the fresh-keeping bag or film have good ventilation and fresh-keeping performance, and the ordinary plastic bag will rot and deteriorate the food after a long time, and the purpose of fresh-keeping cannot be achieved.
4. It is best to use colorless and transparent fresh-keeping bags.