1. Open the pure milk and pour it into the yellow plastic lunch box.

2. Pour the pure milk into the yellow plastic lunch box and cover it, as shown in the figure.

3. Cover the plastic lunch box and shake it for one minute, so that the milk can cover every corner of the lunch box.

4. Pour out the pure milk from the plastic lunch box below.

5. Then wash it in rice washing water.

6. The yellow plastic lunch box will return to its original state.

Extended data

Plastic products also have shelf life. After expiration, the plastic will age, change color and become brittle. If the used plastic box is found to be yellow or no longer transparent, it should be replaced as soon as possible. The plastic lunch box will be uneven after being used for a long time. If the missing part is not good, it will be eaten by people.

Consumers must pay attention to the shelf life of plastic products. At the same time, aging plastics may release substances harmful to human body. As for the "life" of a plastic lunch box, it depends on personal use and cleaning methods. The shelf life of most plastic products is generally about three to five years. If you use it frequently, it is best to replace it once every one or two years.

Every plastic has a heat resistance limit. Among the food materials, the most heat-resistant is polypropylene (PP), which can withstand 140℃, followed by polyethylene (PE), which can withstand 1 10℃, and polystyrene (PS), which can only withstand 90℃.

At present, the plastic lunch box for microwave ovens is mainly made of PP or PE. If the temperature exceeds their heat resistance limit, plasticizers may be released. If a large amount of plasticizer is ingested for a long time, it may damage the liver and kidneys and affect development and growth.

Therefore, it is necessary to avoid heating food with high-temperature heating plastic lunch boxes for a long time.

Baidu encyclopedia-plastic lunch box

People's Network-The lunch box takes too long, so be careful to eat "plastic".