Classification
Most of the cling film and commonly used plastic bags sold on the market are made from ethylene-based materials. According to the different types of ethylene-based materials, cling film can be divided into three categories.
The first is polyethylene, abbreviated as PE. This material is mainly used for food packaging. The film used for fruits and vegetables we usually buy, including semi-finished products purchased from supermarkets, uses this material;
The second is polyvinyl chloride, abbreviated as PVC. This material can also be used for food packaging, but it has a certain impact on human health;
The third is polyvinylidene chloride, abbreviated as PVDC, mainly used for packaging some cooked food, ham and other products.
Among these three types of cling film, PE and PVDC cling film are safe for human body and can be used with confidence, while PVC cling film contains carcinogenic substances and is more harmful to human body. Therefore, when purchasing cling film, PE cling film should be selected.
From a physical point of view, cling film has moderate oxygen permeability and humidity permeability, adjusting the content of oxygen and water around the preserved items, blocking dust, and thus extending the shelf life of food. Therefore, it is necessary to choose different cling film for different foods.
Cling film on the market is generally divided into two categories: one is ordinary cling film, suitable for refrigerator preservation; the other is microwave cling film, which can be used for both refrigerator preservation and microwave oven. The latter is far superior to ordinary cling film in terms of heat resistance and non-toxicity. Therefore, consumers should pay special attention to the selection and use of different types.
Characteristics
Ideal cling film should meet the following conditions:
1. Easy to pull out and cut;
2. Easy to adhere to glass, ceramic and stainless steel tableware (but not the cling film itself);
3. Nearly transparent and without wrinkles, and no uneven thickness;
4. Can withstand general pulling pressure.
Uses
1. Cover food containers to prevent bacterial infection.
2. Wrap food for convenient storage (e.g., sandwiches).
3. Refrigerate soup bowls covered with cling film to remove oil from the soup.
