People misunderstand stainless steel, thinking that it contains chromium and is toxic. In fact, there are high contents of chromium and nickel in stainless steel. Under normal conditions, the surface of stainless steel is in a passive state, and its chemical properties are very stable. It is very safe to use as tableware, including rice cookers. It can also be simply said that stainless steel is non-toxic. The extensive use of stainless steel in milk factories, chemical pharmaceutical factories and medical devices is a good example.

Stainless steel has been in contact with salty food for a long time, and chromium and nickel in its components may be corroded and dissolved to form chromium and nickel compounds. Among them, hexavalent chromium is a serious drug, and nickel compounds can also cause skin allergies, among which hexavalent chromium is the most toxic. If the content of hexavalent chromium in water exceeds 0. 1 mg/L, it will have toxic effects on human body. Hexavalent chromium has serious irritation to the skin, which can cause skin ulcers, and long-term intake will cause cancer. The wastewater and waste of hexavalent chromium can't be naturally degraded in nature, but accumulate in organisms and human bodies, which will lead to long-term harm. It is a highly toxic carcinogen and a serious corrosive medium. U.S. Environmental Protection Agency (EPA) identified hexavalent chromium (note: it is not metallic chromium) as one of 17 highly dangerous toxic substances. The European Union has made very strict restrictions on the use of hexavalent chromium in automobile parts. China also listed hexavalent chromium in the first batch of National Hazardous Waste List. The rice cooker is only used for cooking, and it is not used for long-term filling of dishes containing salt, but only in contact with rice and water. At this time, the stainless steel is in a passive state and its chemical properties are very stable, so there is no need to worry about using stainless steel rice cookers.