What Does a Bulging Can Indicate?

A bulging can may indicate that gas-producing bacteria have multiplied inside. This is a serious food-safety warning. A bulging can must always be inspected before it is opened. What causes a can to bulge? If a can is not heat-processed adequately during production, bacteria that survive inside may produce gas over time and cause the can to swell. One of these, the bacterium associated with botulism, poses a serious risk of food poisoning. A bulging can should never be eaten. A dent or rust may sometimes make a can look swollen, but it can be difficult to distinguish gas-related swelling from physical damage. Throwing away a suspicious can without opening it is recommended. What other signs should you watch for? In addition to bulging, a hissing sound when opening a can, a bad smell, or foamy contents can be signs of spoilage. If any of these signs are present, do not eat the food; throw it away. Cloudy liquid or an unusual color inside the can is also a warning sign. In a fresh can, the liquid is usually clear or has a color appropriate for the ingredient. How should you discard a bulging can? Throw it away unopened. Even trying to open it may release built-up gas or bacteria into the surrounding area. Washing your hands and any surfaces with soap and water is recommended. Do not give a bulging can to pets; they face the same risk of food poisoning. How should canned food be stored? Store cans in a cool, dry place away from direct sunlight. High temperatures can speed up bacterial growth inside a can, while damp conditions can cause the outside to rust. After opening a can, transfer the contents to a sealed glass or plastic container and refrigerate them rather than leaving them in the can. Food left in an open can may develop a changed flavor from contact with the metal. Can canned food past its expiration date still be eaten? A can that is past its expiration date but is not swollen or damaged may often remain safe for a short time, though its flavor and nutritional value may decline. When in doubt, throwing it away is safer than taking the risk. Inspect the outside of a can before opening it; deep scratches, dents, or rust spots may indicate damage to the inner lining. Such cans should be assessed carefully even if they are not swollen. When shopping, choosing cans from different places on the shelf instead of always taking one from the back may help reduce waste. Whichever can you choose, check that it is properly shaped and its exterior is intact. Check the smell after opening: if the food smells sour or sharp, spurts or foams when opened, looks discolored, or shows mold, throw it out without tasting it. A normal smell does not prove the food is safe, though, because the toxin that causes botulism cannot be seen, smelled, or tasted.