There are such things as "Food Grade" Rust inhibitors, usually oil based, as already suggested. Depending on your HACCP definition of "Food Grade" and what auditors expect, is what will limit (or expand) your choices of product. It is also worth considering what the rust prevention time desired is, and the environment it is stored in. Short term, dry and non-humid environment will allow almost any suitable product to be used. High humidity, warm environments will require a more complex product. Short-term (days) is easy, long-term (months) is more difficult.
* At the "safest" end of the spectrum are edible oils, but without additives to enhance stability, these are generally very short term.
* Next are NSF category code products such as 3H (www.nsf.org) which are ideal for short-term anti-corrosion where food contact is going to occur (e.g. meat hooks).
* For improved corrosion protection, H1 lubricants offer a more diverse range of options but must be removed prior to food contact (only accidental contact allowed). In this category, you will find oils with an additive package to improve performance.
* NSF H2 category really opens things up, but the proviso is that there must be NO food contact, so removal and rinse is vital. Although classified as "lubricants" there are plenty of options marketed as "anti-corrosion" as there is no definitive NSF category for this.
* Finally, if your definition of "food grade" is based on a robust HACCP audit that identifies non-NSF registered or non-FDA ingredients (basically any old industrial stuff) then these maybe suitable, but the onus on the documented risk reduction is key to safe use.
The above may classified as "temporary" protection from corrosion - even if the time is measured in a couple of years. For "permanent" protection, you are looking at paints and the NSF category code R1 or R2.
Regards,
Kieran
