Stainless steel kitchen equipment long-term contact with acidic materials will cause corrosion of stainless steel, thereby releasing the heavy metal chromium, long-term use will cause chromium poisoning, seriously endangering human liver function.
As long as stainless steel kitchenware does not corrode during use, chromium in stainless steel kitchenware will not migrate to food, nor will it cause chromium poisoning. The corrosion resistance of high quality stainless steel kitchenware is very good, and generally does not cause chromium poisoning. However, it should be noted that acidic substances are indeed corrosive to stainless steel, which will dissolve chromium in stainless steel, and should be prevented as far as possible when using stainless steel kitchenware.
When salt and vinegar are mixed, hydrochloric acid is produced. High concentration of vinegar and salt will corrode stainless steel cookers and remove chromium at high temperature for a long time in stainless steel cookers.
根据中国《食品安全不锈钢产品标准》(GB 9684-2011)，不锈钢产品中铬的迁移量不能超过0.4 mg/m2。前卫生部在设定限量标准时解释说，一般不锈钢产品在储存、烹调或与食品接触过程中不会构成食品安全风险;当不锈钢制品在使用过程中转移的铬超标时，可能会对人体健康造成危害。
According to China National Standard for Food Safety Stainless Steel Products (GB 9684-2011), the migration of chromium in stainless steel products should not exceed 0.4 mg/m2. The former Ministry of Health explained that stainless steel products generally do not pose a food safety risk in the process of storage, cooking or contact with food; when the chromium transferred from stainless steel products in use exceeds the limit, it may cause harm to human health.
China's quality inspection authorities have repeatedly said that chromium is irritating and corrosive to skin, mucosa and digestive tract, and easy to enter human cells. Inhalation of high concentrations of chromium can cause damage to the liver, kidney and other visceral organs. The accumulation of chromium in the body is carcinogenic and may induce gene mutations.
Since chromium is harmful to health, why not require stainless steel cookers to be chromium-free? The answer is No.
Stainless steel is not rusty and has good corrosion resistance, because the surface of stainless steel can naturally form a stable, compact and high strength passivation film, while chromium is an important component of the passivation film on the surface of stainless steel. The passive film of high quality stainless steel kitchenware is firm and stable, and has good corrosion resistance. It will not fall off or dissolve in normal use, so chromium will not dissolve out and migrate to food to cause poisoning.
"However, low-quality stainless steel kitchenware has poor corrosion resistance, is easy to corrode, rust and contaminate food, and has a certain risk of chromium poisoning." Stainless steel should contain not only chromium, but also enough chromium. Stainless steel products usually contain 13% or more chromium to avoid corrosion. Low-quality stainless steel cookers are prone to rust due to the low chromium content. Chromium should have a protective effect, but it will migrate to food and cause health hazards. Therefore, in order to avoid chromate poisoning caused by stainless steel kitchenware, we must first ensure the quality of stainless steel kitchenware itself. Secondly, "if you encounter stainless steel kitchenware which is easy to rust, it is not necessary to use less."
According to the quality inspection department, stainless steel kitchenware should avoid long-term contact with acid and alkali materials; do not use stainless steel cooking utensils to boil traditional Chinese medicine, in order to avoid the reaction between stainless steel heating conditions and alkaloids and organic acids in traditional Chinese medicine, so that chromium precipitation; stainless steel kitchenware deformation or surface wear, rough, should be replaced in time.