As a life rule, you don't want to eat food that's well-past its expiration date. Sure, there's a little wiggle room, as those dates are guidelines. But 60 years past expiration -- well, now you're you've thrown out life rules and abide by death rules. Or something close to it.
YouTuber Steve1989 MREinfo recently posted a review after consuming several Post-Korean War-era Ration, Combat, Individual (RCI) cans, the first US-made, 24-hour rations. Several B-unit cans date back to 1951, while accessory cans date to 1955. For the review, Steve dug into the cans from 1955.
"Smells nice," Steve said, as he opened the first can. "Man, I hope I don't get botulism from this," he said after testing the jam.
Unfortunately, the seedless blackberry jam leaked in the can. But Steve powers through to test out said jam, crackers, a cocoa drink, and half a can of peanut butter. And he didn't die (so far as we know)!
"That's disgusting," Steve says about his drink. "It tastes like you took Cool Water, and added hot chocolate to it."