If a can of soup is undamaged and stored in a cool, dry place, the soup should be safe to eat for two to five years or longer. However, the taste of the food will gradually diminish over time.
Canned meat and vegetables have a low acid content, while fruits, including tomatoes, have a high acid content and should only be stored for 18 months or less.
Canned foods should be stored in a dry, cool place where they will not be exposed to extreme temperature fluctuations and potential water damage. For this reason they should not be stored in damp spaces such as underneath sinks, in garages or above stoves.
Botulinum toxin is extremely rare, but can be a fatal hazard in foods stored in damaged cans. If the can is bulging, badly dented or leaking, you should discard it. If the food has a foul odor or the can is spurting liquid upon opening, do not eat it or even taste it, as it can be deadly.