There are many videos on YouTube by tasters investigating old beers, wines, and foods. I find many of them of good interest. In some cases the products taste almost unchanged, or rate better to today’s equivalent.
In others spoilage is evident.
Obviously anyone thinking to try this must exercise due caution. Personally I don’t think I would taste any food significantly out of date, with cans given more leeway perhaps.
I have tasted numerous old beers in my time, as beer cannot acquire, at least so I have read, pathogenic properties due to the ethanol, but even then due caution is needed.
I take a common sense approach: if a smell is offputting, leave it alone. Anyway, caveat emptor.
In a July 2021 video, a British taster on the Real Ale Craft Beer channel compares Guinness Extra Stout of 1955 to today’s version. His actual tasting starts at 8:25 in the film.
He is very descriptive in his analysis. It sounds like the beer has gone tart to a degree but he doesn’t mind it.
He finds too it has a bigger body than today’s beer. There is more: e.g. it leaves no sediment. Watch if so inclined.