Many of us understand that when it comes to a cold or the flu, we're most contagious before we start feeling sick; that by the time we've got a runny nose, sore throat and achy muscles, the damage to the people around us has already been done. In fact, many of us are completely wrong.
Immediately refrigerate leftover canned tuna in a glass or plastic container. Do not leave the tuna in the opened can, as it may become rusty once open. You can refrigerate canned tuna in a tightly covered container for up to two days. If you are storing your canned tuna in an unheated garage, ensure that it does not freeze during the winter months. This can cause the can to bulge or rust.
They are also coated with a plastic lining that insulates the food from the metal can. According to the USDA it is perfectly safe to store food in an open can for a couple of days. After that, depending on the type of food, the food begins to degrade as it would in any other type of container in the fridge. The best purchase I have ever made was for a side cut can opener that is just the cat's meow.