1, first of all depends on whether the appearance of the plastic bag "for food use" sign. Usually the logo should be on the front of packages, and prominently position. Next is to look at the color, generally speaking, colored plastic bags are used in the recycling of waste plastics, and cannot be used to hold food. For example, some market for fish, shrimp and other seafood or meat and black plastic bags, were originally used to hold waste, consumers should avoid using. Finally, to see plastic bags are free of impurities. Place the plastic bag in the Sun or light, see if there are black spots, there are no cut. Plastic bags with the impurities must be using waste plastics as raw materials.
2, the smell of plastic bags have no smell, make people feel sick. Qualified plastic bags should be odor-free, additive was ineligible due to the use of plastic bags, with a variety of flavors.
3, qualified plastic bags with a certain strength, will not tear easily and unqualified plastic bags by the addition of impurities, often very poor, easily breakable.
4, qualified plastic bags in case of jitters, tinkling noises unqualified plastic bags tend to be "buzzing" sickening thud.
5, put plastic bags in the water, with your hands to press it into the bottom, wait a minute, surfaced for nontoxic plastic bags, sank at the bottom of the poisonous plastic bag.
6, hand touching the surface of the plastic bag, very smooth and is not toxic. If the color blending, and touch the sticky, itching is toxic.
7, and burning: will plastic bags cut Xia a angle, put in fire Shang a burn, nontoxic of burn of that burning, will it left fire Hou still continues to burning, and appeared yellow flame, and melt statue candle as a drops a drops down off, issued paraffin smell; toxic of, easily burning, burning Hou is green flames, and has a unit choke nasal of odor.
Plastic bag less to heat, oil and food. Of course, you cannot determine whether the plastic bag under the premise of security, avoiding use it to contain overheating or fat food, is one of the methods of harm reduction. Experts said Lu Sihao, unsafe plastic bags, which mainly contain dyes, heavy metals and other hazardous substances. Oily foods such as meat, fish, and fried dough sticks grease is actually contained in a solvent, it can make the precipitation of harmful substances in plastic bags; and the heat will soften the plastic, can also promote precipitation of harmful substances, toxic. Therefore, packed vegetables at room temperature or frozen food, will be relatively safe. Of course, I should try not to use plastic bags containing food. Can I buy food with a basket or bag, forced to use, after returning home, should also take out the plastic bags of food as soon as possible.