Why Do Canned Foods Need Expiration Dates?

Canned foods do not need expiration dates because they are safe to eat indefinitely, notes the USDA Food and Safety Inspection Service. If the cans are not swelling, rusty or dented and have not been frozen, the food inside remains good indefinitely.

The way canned food is stored has a greater impact on its edibility than the length of time it has been in a can. Extreme heat or temperatures that vary between extreme cold and heat can damage canned food. Canned food that contains added salt lasts longer than unsalted food of the same type and acidic canned foods have the shortest shelf life.