Food-Grade Anodic Coatings
Anodizer looks for certification that an anodic coating is safe to use with food.
Q. I work with a large, global company in India. Parts that we anodize are used directly in food manufacturing and packaging. We want to be sure these hard-anodized (Type III) parts are compatible with operations and would like to get an independent laboratory to certify that the anodic coating is safe to use with food. Can you give us some guidance on this issue?—V.M.
A. It could depend on the country where these items will be sold. I have not had any experience with the regulations governing the use of anodic finishes with food production in any country except America. In the United States, the Food and Drug Administration (FDA) is the regulating agency for determining food-grade cooking surfaces. My experience in this area has been that aluminum oxide coating is not regulated, nor is bare aluminum. The FDA will not give a certification or approval for items that are not regulated, it will only say that aluminum, either anodized or bare, is not regulated. I cannot speak for other countries, but I think it’s likely to be the same as in the U.S. I don’t know of anywhere that anodic coatings on aluminum are regulated, but my word on this subject is strictly unofficial.
Electropolishing can be a pretreatment for anodizing or a substitute for bright dipping. Either way, it improves the surface of the aluminum...
The following anodizing process overviews are provided as a means of introduction to aerospace anodizing
How it’s produced, NSS testing and how to get the best results possible.