For a stainless steel to be considered ‘food grade’ and to come in contact with food stuffs it must be approved by the US Food and Drug Administration (FDA) and other regulatory bodies. To be approved as foodsafe, stainless steel must have a minimum chromium content of 16%. The chromium content is what helps protect stainless steel from rust and corrosion. Stainless steels contain sufficient chromium to form a sort of film or coating of chromium oxide, which blocks oxygen diffusion and therefore corrosion to the steel’s surface and from spreading to the steel’s internal structure.
Stainless steel with a chromium content of less than 16% may be used for other food uses, such as cutlery and blades, but is not safe for prolonged food contact such as food grade stainless steel containers.
304 stainless steel (also known as SAE 304 SS, A2 Stainless or 18/8 stainless) is the most popular austenitic crystalline steel. It has a chromium-nickel alloy which gives it the best corrosion resistance out of the food grade steel families.
The 304 stainless steel is particularly strong and popular due to its composition of 18% chromium and 8% nickel. a austenitic crystalline structure, chromium-nickel alloy. You read that right. Eighteen percent chromium. That’s above the FDA minimum of 16% chromium, so yes, 304 Stainless Steel is FDA approved.
It is also American National Standards Institute (ANSI) and National Science Foundation (NSF) approved for food contact, as they have the same minimum chromium content.