Canned foods may be shelf-stable, but for how long?

The COVID-19 pandemic has shifted life for many of us. While most of us are still able to run essential errands and get exercise, health officials have suggested limiting your trips to the grocery store. So if you're looking to stock up on your next grocery run, canned food is an affordable, healthy option to replace fresh produce or protein.

grocery store canned goods aisle
Credit: Getty / Jeff Greenberg / Contributor

If you already have a pantry full of canned foods, you may be wondering if they're still safe to eat. Canned foods are known for having a long shelf life, but how do you tell if a can has been in your pantry for too long? We turned to the USDA's guide for shelf-stable food to answer our questions. Here's what we found.

How to Store Canned Foods

According to the USDA, canned foods should be kept in a cool, dry location (ideally below 85 degrees Fahrenheit). A pantry or cabinet works, but you should never store them above or beside the stove or sink. Those locations could create a damp environment or extreme temperatures. Environments that are too hot increase the risk of spoilage, whereas environments that are too cold could cause cans to swell.

What to Do If Your Can Is Rusted

Canned food undergoes a vacuum-sealing process in order to keep it fresh and prevent any new bacteria development. If your can is heavily rusted on the outside, the USDA says to discard it. Rust can lead to tiny holes, which allow bacteria to enter. If your can has a little surface rust that can be easily wiped off, it's probably safe to use.

What to Do If Your Can Is Dented

If your can has a small dent, the food should be safe. The USDA advises throwing out deeply dented cans—FYI a "deep dent" is defined as "one that you can lay your finger into" or one that has sharp points. If the seam of your can has been dented, discard it, as the vacuum seal has likely been compromised.

What to Do If Your Can Is Swollen

A swollen can indicates that the food inside has expanded. The USDA says to throw out any swollen cans as they could be contaminated with Clostridium botulinum, a type of bacteria that not only causes food spoilage but could also lead to botulism, a severe—and potentially deadly—form of food poisoning.

What to Do If Your Can Is Frozen

A frozen can is safe to eat as long as it has been thawed safely in the refrigerator and shows no signs of swelling. The USDA recommends then boiling the food for 10 to 20 minutes before eating. If the can has been thawed in an environment above 40 degrees Fahrenheit, it should be thrown out. If you're unsure about the contents, don't risk it!

What to Do If Your Can Makes Noise When You Open It

When you open a canned product, you're breaking the vacuum seal, so it's normal to hear a release of air. But, the USDA warns that if a can "hisses loudly or the contents spurt forcefully out of the can when opened" the product could be unsafe. If that is the case, dispose of it immediately.

How Long Do Canned Goods Last?

While there is no official timeline, the USDA's FoodKeeper App says low-acid canned goods (such as canned meat, soups, gravies, beans, and vegetables) can safely last 2 to 5 years in the pantry. High-acid foods (such as fruit juice, tomato soup, foods in a vinegar-based sauce, or sauerkraut) can last 12 to 18 months in the pantry. Both types can be eaten past their use-by or best-by date, as long as they don't show any signs of dents, rust, or swelling.

These tips are good to keep in mind before eating any canned food. But the old adage still rings true: "When in doubt, throw it out."