A few years ago friend of mine moved back into the area and I offered my spare room. He moved in and we would take turns making lunch and coffee in the mornings before work. Well, I have a large cabinet with canned foods and such that is rather deep and I'm not the most organized person. So we ran out of mayonaise and he found a jar in the back of the cabinet and started using it for sandwiches. After two weeks of eating it I realized that it was over three years expired! Neither of us got sick so we laughed and used it up. It was kept in a cool dark place but still I figure if I eat a little and it does'nt affect me it should be alright.