I am in the process of making the cook's illustrated recipe for pork pernil. For the first hour, you heat marinated pork at 450, covered tightly in a roasting pan with aluminum foil.
Lo, pulling it out of the oven I see several tiny spots where the aluminum foil has been eaten away. The edges are black-ish, which suggests galvanic corrosion, what's commonly called a "lasagna battery" or "lasagna cell" - the results of 2 metals sandwiching a piece of food that is acidic. I was using a stainless steel roasting pan, and basic aluminum foil.
The spots are tiny, and they're shotgunned all over the top of the pork. They're very small, and they're in several clusters, but overall MOST of the pork wasn't impacted. It would be difficult to scrape it off because it is so small. This is a huge cut of meat, and I'd hate to throw it out, but I don't know if the galvanic reaction can do any other damage.
So, is it safe to eat?