Abstract: Plastic packaging bags are our daily necessities, but it should be noted that some plastic packaging bags are toxic and cannot be used to directly hold food. Non-toxic plastic bags are made of polyethylene, polypropylene, melamine and other raw materials. Plastic bags made of polychloroprene are toxic and cannot be used as food packaging bags. The main methods to identify non-toxic plastic packaging bags are to look at the color, listen to the vibration, touch with your hands, smell with your nose and so on. The choice of food packaging bags should pay attention to whether there is food, and try to choose materials that are not coated or electroplated. Let's take a look at the identification and selection methods of plastic packaging bags! How to identify toxic plastic packaging bags

1, observe with eyes

Non-toxic plastic bags are white, transparent or slightly transparent, with uniform texture; Toxic plastic bags are colored or white, but the transparency is poor, turbid, and the plastic surface is stretched unevenly with small particles.

2. Listen with your ears

When the ear listens to the plastic bag vigorously shaken by hand, it makes a crisp sound, indicating that it is a non-toxic plastic bag; And the noise is small and stuffy. It's a poisonous plastic bag.

Step 3 touch with your hands

Touch the surface of plastic packaging bag with your hands, which is smooth and non-toxic; Sticky, astringent and waxy are all toxic.

Step 4 smell with your nose

Non-toxic plastic packaging bags are tasteless; It is toxic to have a pungent smell or an abnormal taste.

5. Underwater test method

Submergence test: put the plastic bag into the water, press it to the bottom by hand, wait a moment, and the non-toxic plastic bag will surface and the toxic plastic bag will sink to the bottom.

6. Combustion method

In the combustion test, the non-toxic plastic bag is flammable, and the flame tip is locally yellow and blue. When burning, it drips like a candle and tears, and it smells like paraffin. Toxic plastic bags are not easy to burn and will be extinguished immediately after leaving the fire. The tip of the flame is yellow and the bottom is green, so it can be softened and drawn.

How to choose food packaging bags correctly

1. The outer packaging of plastic packaging bags for food shall be marked with the name of the factory, the address of the factory and the name of the product in Chinese, and the words for food shall be marked. After leaving the factory, all products are accompanied by product inspection certificates.

2. Plastic packaging bags for food are odorless and tasteless when they leave the factory. Plastic packaging bags with special smell cannot be used for food packaging.

3. Colored plastic packaging bags (dark red or black colors currently used in the market) cannot be used for food packaging, because such plastic packaging bags are often made of recycled plastics.

4. Try to use uncoated and electroplated materials. In modern packaging design, in order to make packaging more beautiful and corrosion-resistant, a large number of coated materials are used. This not only makes it difficult to recycle and reuse waste materials, but also makes most paints toxic. If people eat these packaged foods, it will do great harm to people's health.

In addition, the coating and electroplating processes have also brought great pollution to the environment. For example, paint volatilizes toxic solvent gas, and waste liquid and waste residue containing heavy metals such as chromium are produced during electroplating. Therefore, we should try to choose uncoated and electroless packaging materials.

It's best to buy food in big shopping malls instead of street stalls.

6. Because plastic packaging bags for food are not easy to degrade, it will cause environmental pollution. Therefore, when buying food, it is best to choose green packaging materials. Paper is the most widely used green packaging material at present. Therefore, it is best to buy food in raw paper packaging, and biodegradable plastics can also be used.