Tuna from 17 year-old MRE is more like eating what I think Alum might be like but it didn’t kill me. The other contents were similarly just OK. Tobasco sauce however is just like new.
Or opening the wrong end of beans and franks to dig into 1/4" of congealed grease. We did not get MRE's, they were sometime later. We did grab some sort of pouch type food the army got now and then. IIRC, not to bad if you could find some hot water.