Can plastic bags be used to hold hot food? Will it be toxic?

Candies, biscuits, preserves, fruits and other foods are packed in plastic bags. Through a crystal clear film, they not only look attractive in color, but also isolate bacteria and keep them clean. Can make the food that needs a certain amount of water not dry, and the food that needs to be dried does not regain moisture. Another advantage is that it is easy to carry and it is not easy to break when packing.

However, someone may tell you that it is good to pack food in plastic bags, for fear of toxicity. So, is it poisonous to pack food in plastic bags?

Generally speaking, plastic bags specially used to hold food are harmless because they are made of polyethylene or nylon. The high-pressure polyethylene film looks and feels a bit like a thin layer of paraffin. Fortunately, the composition and structure of polyethylene are indeed very similar to paraffin, except that the molecule of polyethylene is much larger than paraffin. Nylon membrane is stronger than polyethylene membrane, but its cost is higher, so its application is not so common.

There are many ways to make polyethylene, and the most common one is to polymerize ethylene at 200 ~ 300℃ and 1000 ~ 2000 atmospheric pressure. In polyethylene, no other substances are doped. The polyethylene prepared by this method has low density, soft texture and high stability to sunlight, air, moisture and chemical reagents, so there is no need to add stabilizers and plasticizers, which are mostly toxic or highly toxic.

It is safe to use this polyethylene film as a food bag, because it is non-toxic, but it also has certain air permeability. If it is used to wrap spices or smelly things, it is not suitable, because some aroma or smell will escape. In this case, nylon membrane is more ideal.

As for whether plastic bags made of films made of other plastics are toxic or not and whether they can hold food, it needs specific analysis. For example, polyvinyl chloride, its plasticizer and some residual vinyl chloride are toxic; Another example is polystyrene, in which some styrene molecules can be dissolved in oil, which is also harmful to human body; When the plastic synthesized with formaldehyde as the basic raw material comes into contact with water, other aqueous liquids, grease, etc. Especially at room temperature or above, methanol will dissolve into food, which is a very harmful compound and often causes death. Most disposable plastic bags used now are toxic.

Therefore, unless it is marked as a food plastic bag, or it is completely certain that the plastic bag used is pure polyethylene or nylon, never use any plastic bag to hold food, especially the plastic bag containing pesticides or chemical raw materials. White pollution is becoming more and more serious. In order to protect the environment, you'd better pack food with less disposable plastic bags.