Canned food is one of the best long-term forms of stored food. Most survival blogs recommend storing a substantial amount of food in cans. However, there are some advantages and disadvantages to consider.
The advantage to commercially-canned food is that it keeps for a long time without refrigeration. The foods are pasteurized to kill pathogens by putting the food under high temperatures and high pressure, so that the temperature of the liquid exceeds the boiling point. Boiling at ordinary pressure (and 212 degrees) is not sufficient to kill all pathogens, especially bacterial spores, a dormant form of bacteria that can survive difficult conditions. Commercially-canned foods will keep from one to five years — if the cans are kept dry, undamaged, and at or below room temperature.
Even with the temperatures and pressure of commercial canning, some bacterial spores, called thermophiles (heat-loving), can survive. These bacteria are not pathogenic, but they can spoil the food, if the cans are exposed to hot temperatures. The FDA says:
Many canned foods contain thermophiles which do not grow under normal storage conditions, but which grow and cause spoilage when the product is subjected to elevated temperatures (50-55°C). (Examination of Canned Foods)
50 degrees Centigrade is 122 degrees Fahrenheit. If you keep canned goods in a storage shed or garage, the temperatures could reach high enough to activate these thermophilic bacteria.
If you store canned goods in your basement, you will avoid this high-temperature problem. But basements tend to be damp, offering another problem for long-term storage: moisture. Most cans are made from steel and can rust if exposed to moisture. For long-term storage, a can may rust through, spoiling the food. Damages or dented cans tend to rust more easily. Canned goods in a moist environment should be kept inside another container that is sealed to keep out moisture. Silica gel packs can be used in a sealed container to absorb moisture.
Another approach is to store what you use, and use what you store. You then rotate your canned goods, using stored food and replacing it when you grocery shop. In this way, the canned goods are kept fresh. You don’t have to worry about whether the foods are beyond their ‘best by’ or ‘expired’ dates.
Disadvantages to canned foods are that the cans are heavy, and typically contain a lot of water. Freeze-dried foods offer long storage times and light-weight. Certain dried foods keep well without freeze drying or canning: dried legumes, white sugar, white rice, white pasta, etc. The whole grain versions of rice and pasta do not keep as well, because oils in the bran can go rancid after less than a year of storage.
The television series “Life After People” has an entertaining and instructive episode on what happens to food when various storage methods fail. See time marker 26:09 and following for canned goods. High temperatures allow thermophilic bacterial in the cans to grow, producing gas that eventually bursts the can. (Lots of other interesting info of food storage failure in that episode.)