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Toxicity of Chromium in stainless steel - Hexavalent vs Trivalent
Q. 1. We hear lot about toxic nature of hexavalent chromium. It is said that trivalent chromium is lot safer. Can someone put these onto a scale please?
2. What about stainless steel (18+ % chromium)? Are stainless steel food containers and cooking utensils safe enough? If so, by how much? Do we need to take account for chemical reactions that take place, during cooking and storing, particularly acidic ingredients such as wine, vinegar
[in bulk on
eBay or
Amazon], lemon juice etc.? Thanks.
end user - Melbourne, Vic., Australia
July 30, 2008
A. Hi, Bob. Here in the USA we would rely on the FDA to evaluate the safety of materials for food containers. I'm sure you have a similar government department in Australia but I don't know its name. Stainless steel is very safe. Most food processing and pharmaceutical equipment in factories is required to be stainless steel.
The chromium in stainless steel is in metallic state (oxidation state 0, not +3, and not +6); it is neither trivalent nor hexavalent. Stainless steel is highly corrosion resistant. A very strong acid (not vinegar or lemon juice) might dissolve it and put some of the chromium into the trivalent state, but you cannot raise it to hexavalent state without a strong oxidizing agent or electricity. We can't give you a scale of toxicity for trivalent vs. hexavalent because trivalent can be a dietary supplement whereas hexavalent is a carcinogen.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 31, 2008
Q. I read somewhere that stainless boilers are prohibited because they produced hexavalent chromium. Will boiling Maple sap in a stainless steel vessel with a direct flame and then sealing the vessel for a few years contaminate the product for consumption?
Pat Newnam- Edwards, Colorado, USA
March 25, 2011
A. Hi Pat.
It's hard to comment on something read somewhere, but stainless steel is generally very safe.
Still, whether you are making beer, wine, whiskey, maple syrup, or anything else, there is always much to be learned from the enthusiasts and industrialists who continually work in that particular area. I'm from the electroplating industry and have never even read a single magazine about the maple sugar process; I'm out of the loop and a bit unqualified to comment on proper materials of construction and methods. Sorry!
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
December 15, 2012
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