I don’t understand how canned foods stay fresh indefinitely. Could someone explain it to me? I feel very dense, as though I should know this but don’t. Help!
Well, they are “cooked” to kill bacteria and then sealed in a vacuum. All the nasties that would spoil the food need air to function, so they can’t start growing until the can is opened.
There is still a shelf life on them though. I believe the acidic foods,like tomatoes and pickles keep longer.
Well, they don’t stay fresh, they stay canned, and one hopes they remain edible. When you can something you first sterilize the jars or cans and also do your best to eliminate life from the food to be canned as well. Since there is nothing left alive and the cans are sealed, the food doesn’t deteriorate further unless in interacts chemically with the container or the seal is broken. Glass jars are fairly inert and you may have noticed some foods in cans with a white interior. This white interior is a so that the foods, especially acidic foods like coca-cola, do not chemically interact with the metal of the can.