Last year, 2020 we cleared out and sold my parents home of 62 years. My mother was an amazing canner, beats, chow chow, vegetables and venison, pressure and water bath. We raised a 180 + 60 garden every year growing up and hunted. In the back of her canned food pantry at the bottom was a quart jar of pears canned in 1988 by my aunt who died in 1989 and a pint jar of peach preserves canned by by grandmother in 1983. Both are very dark but the seals are good on both jars. My sister and I have them and are mulling over opening one of them. My grandmothers peach preserves were the stuff of legend and I’m sure that’s why mom saved them for nearly four decades. I’ll post what our taste test proves! During the late 90’s I tried some canned goods from a civil defense bunker. There was spam, stew and tinned crackers, tinned cheese. All were just fine and none of us fell ill. It was placed there in 1958 so about 40 years. They were sealed in a drum we opened.