A while ago I found some canned corned beef that was nearly 15 years past its pull date in the back of a cupboard. I had heard that canned meat could stay edible for a long time if it wasn’t stored at extreme temperatures, so I tried an experiment. One of the cats ate some with every sign of enjoyment and no ill effects, and I ate the rest of the can with saltines. The meat tasted pretty metallic, but I didn’t get sick.
If you cook it a longer time and add some salt and pepper, or spices you like, you can significantly reduce that metallic taste.