1.smell method.  
The silicone rubber products close to the nose smell, the pungent smell is ordinary silicone rubber, on the contrary, it is food grade silicone rubber. Ordinary silicone rubber with a pungent smell, is not environmentally friendly silicone rubber. And food grade silicone rubber is non-toxic and tasteless, belongs to environmental protection silicone rubber.

2.force pull method.
Take the silicone rubber tube for example, hold both ends of the silicone rubber tube by hand and pull it in the opposite direction. If it is pulled white and you can smell a strong smell, it means that it is ordinary silicone rubber, while it is food-grade silicone rubber. (Sometimes it will not turn white when it is pulled up. Because the manufacturer produces by-products in the process of vulcanization, there will be a light smell, but it is also food-grade silicone rubber, which will not affect the quality of the product, and this smell can be eliminated by itself).

3.baking method.
In addition to special silicone rubber, the general temperature resistance of ordinary silicone rubber can only reach about 150 degrees, while food grade silicone rubber can withstand high temperature of 250 degrees, and temperature resistance can be up to 350 degrees in a short time.