Is that food item still ok to eat? Common sense comes in to play here, which certainly makes it difficult for a lot of people. The “Sell By” date is just for the grocer and has nothing to do with safety in eating.
“Best By” date is the most commonly seen out there. It refers to when the product will be at its possible best quality or flavor. The “Guaranteed Fresh” date, usually on bakery items, indicates peak freshness, not that it won’t still be good later.
“Use By” date is the last date the manufacturer indicates peak quality. It will still be good to consume. Getting back to common sense, if it looks bad, smells dad or has growth on it, you should throw it out.
Exceptions would be something like cheese that you can simply cut off the mold and eat. If eggs don’t float in water they are still good. Cooking meat to the recommended temperatures is always a wise move.
Canned goods are what people store in fall-out shelters to eat when the time comes. Storing them in a dry, cool place is helpful. They should last many years. If the can is dented, bulging or discolored you should avoid. Just be smart and use that common sense, it’s in there somewhere.