It is understood that the chemical name of the fast food box material is polyethylene or polypropylene. It has low strength and cannot withstand high temperatures above 80 ℃, with a certain degree of breathability. We can use sensory and combustion methods to identify its non-toxic properties. The details are as follows:

1、的聚乙烯塑料快餐盒为乳白色、半透明体，手摸有石蜡滑腻感，质地柔软能弯曲。放在水中能浮于水面，沸水中显著软化。遇火容易燃烧，燃烧时滴下蜡状物，并有烧蜡气味。火焰为黄色，下端为蓝色，烟少。离开火后仍能继续燃烧。

1. The non-toxic polyethylene plastic fast food box is milky white, semi transparent, and has a smooth paraffin feel when touched. The texture is soft and flexible. It can float on the surface of water and soften significantly in boiling water. It is easy to burn when exposed to fire, and during combustion, wax like substances drop and there is a burning smell. The flame tip is yellow, the lower end is blue, and there is less smoke. Able to continue burning even after leaving the fire.

2、的聚丙烯塑料快餐盒为乳白色、半透明体，手摸润滑但无滑腻感，质地硬挺有韧性，抖动时声音清脆。放在水中能浮于水面，沸水中软化不显著。遇火容易燃烧，燃烧时滴下蜡状物，膨胀，并有石油气味。火焰为黄色，下端为蓝色，少量黑烟。离开火后仍能继续燃烧。

2. The non-toxic polypropylene plastic fast food box is made of milky white, semi transparent material, which is smooth to the touch but not greasy. The texture is hard and resilient, and the sound is crisp when shaking. It can float on the water surface when placed in water, but softening in boiling water is not significant. It is easy to burn when exposed to fire, and during combustion, wax like substances drip, expand, and have a petroleum odor. The flame tip is yellow, the lower end is blue, and there is a small amount of black smoke. Able to continue burning even after leaving the fire.

3、有毒的聚氯乙烯塑料快餐盒的透明度不及聚乙烯，手摸有发黏的感觉，质地柔软富有弹性，遇冷变硬，放在水中下沉。不容易燃烧，燃烧时软化、能拉丝，并有刺鼻的辛辣味。火焰为黄色，下端为绿色，冒黑烟。离开火后慢慢熄灭希望消费者能留神分辨，不要误用有毒的塑料包装。

3. The transparency of the toxic polyvinyl chloride plastic fast food box is not as good as polyethylene, and it feels sticky when touched. The texture is soft and elastic, and it hardens when cold, and sinks when placed in water. It is not easy to burn, softens when burned, can be brushed, and has a pungent and spicy taste. The flame tip is yellow, the lower end is green, emitting black smoke. After leaving the fire, slowly extinguish it. I hope consumers can be careful to distinguish and not misuse toxic plastic packaging.