> Yesterday I made a can of Campbell's Minestrone, and it wasn't until I was
> cleaning up that I noticed it had "expired" in 2005.
I'm sure we've all eaten expired food, knowingly and not. I've got some MRE substitutes that I've kept past the date and tried it along - I wasn't willing to eat it a year past the expiration date because of texture and flavor problems. Nice to know information for when we in the San Francisco Bay Area have our Big One, and that was the reason for the experiment.
I will also say it depends significantly on storage. I used to live in an apartment that had been converted by the owner from a two-story house to two apartments, and he ran the chimney from the oil burner in the basement through the kitchen pantry. In the winter, it got very hot in there, and canned goods did not last through the winter - some of them swelled up noticeably, and we threw them away unopened. If you're storing canned goods in a closed area in the hot summer sun, you may have more problems than if you store them in a cellar on the shady side of the house.