Can Tuna in Cans Spoil in Heat?

Canned tuna has a long shelf life when it is stored properly. Excessive heat can dramatically shorten the life span of canned tuna. Tuna that has been exposed to high temperatures can spoil, even though it is canned, and become unsafe to eat. In regions where temperatures soar during the summer, it is important to plan the storage of canned goods carefully, perhaps adding a cabinet or shelves away from the working area of the kitchen, where it is likely to be hotter.

When stored correctly, canned tuna can keep for up to three years. It should be stored in a place that is dry and cool. Avoid extremes of heat and cold, and always keep canned tuna out of direct sunlight. The best temperature range for storing canned goods is between 50 and 70 degrees Fahrenheit. If stored at a temperature higher than 75 degrees F, there is a risk that the shelf life will be decreased significantly, according to Clemson University Cooperative Extension specialists P.H. Schmutz and E.H. Hoyle, writing on the university's website.

Moist heat should be avoided when storing canned tuna. The moisture can cause the tuna cans to rust and, once that happens, the tuna should be considered unsafe and discarded. Canned tuna should not be stored in cabinets that are under a sink because of the possibility of leaking. Cabinets next to a dishwasher should be avoided because the heat produced by the dishwasher may create condensation in the cabinet. Cabinets over the stove should not be used either, because of the steam and heat from cooking.

If there is obvious damage to the can, such as deep denting or visible rust, it is best to discard the canned tuna. A bulging can of tuna should not be opened. It could be a sign of damage by excessive heat, but it could also be an indication of botulism. Discard the can immediately. If a can is oozing or leaking, the United States Department of Agriculture advises consumers to dispose of the can securely, making sure that animals cannot get at it. When canned tuna has been exposed to extreme heat, the can may look fine. Even without obvious scorching of the label or soot on the can, the tuna could still be spoiled. Trust your instincts. If you open a can of tuna and it doesn't smell or look as it should, discarding it is the safest option.

Leftover or unused canned tuna, whether just the tuna or tuna mixed with other ingredients, should be refrigerated right away. Use a glass or plastic container with a tight-fitting lid. It can be kept for two days. If you are not planning on using plain leftover canned tuna in that amount of time, it can be frozen in an airtight container or freezer bag. For best quality use within four months. Thaw in the refrigerator to use. It is unsafe to leave it out on the counter to thaw.