1. First of all, it is necessary to see if the appearance of the plastic bag has a "food" sign. Usually this mark should be on the front of the bag, which is moe conspicuous. The second is to look at the color. Generally speaking, most of the colored plastic bags use recycled materials of waste plastic, which cannot be used for food. For example, some vegetable markets are used to hold fish, shrimp and other aquatic products or meat black plastic bags, originally used to contain garbage, consumers should avoid using. Finally, it depends on whether the plastic bag has impurities. Place the plastic bag under the sun or the light to see if there are black spots and there are no holes. Plastic bags with impurities must be made of waste plastics.
2, smell a plastic bag with no smell, whether it makes people feel sick. A qualified plastic bag should be odor-free, and an unacceptable plastic bag will have a variety of flavors due to the use of additives.
3, qualified plastic bags have a certain strength, will not be broken a tear; unqualified plastic bags due to the addition of impurities, often very weak, easy to break.
4. A qualified plastic bag will emit a crisp sound when it is shaken; an unqualified plastic bag is often a muffled sound.
5, put the plastic bag in the water, and press it to the bottom of the water by hand, wait a moment, the non-toxic plastic bag that floats out of the water, the toxic plastic bag sinking under the water.
6. Touch the surface of the plastic bag with your hand. It is very smooth and non-toxic. If the color is mixed, it is sticky and sticky, which is toxic.
7. Burning: Cut the plastic bag into a corner, put it on the fire, burn it without poison, burn it and leave it burning, and continue to burn, and a yellow flame appears, and the meltdown like a candle drops down. It emits a paraffin smell; it is toxic, not easy to burn, it has a green flame after burning, and has a odor of a nose.