How Can You Tell if Canned Food Has Botulism?

Canned food is a convenient way to store food for long periods of time but it has the potential to become dangerous if not properly prepared or stored. Botulism is a deadly form of food poisoning caused by a toxin produced by the bacteria Clostridium botulinum.

If canned food is contaminated with this bacteria, the toxin can cause severe illness and even death if consumed. Knowing how to identify the signs of botulism in canned food can help to keep you and your family safe.

Signs of Botulism in Canned Food

The most obvious sign that canned food may have been contaminated with botulism is an off smell or taste. If you open a can and it smells sour or fermented, discard it immediately and do not taste it.

Another indication that canned food may be contaminated with botulism is bulging cans or lids that are not sealed properly. If the lid or seal on a can looks compromised, discard it immediately.

If a can appears to be sealed properly but still contains an off smell or taste, it could be contaminated with botulism. The only way to tell for sure is to test the contents for the presence of C. botulinum bacteria and its toxin. This should be done by a certified laboratory, as attempting to do this yourself could be dangerous.

Preventing Botulism

The best way to prevent botulism from developing in canned foods is to practice proper storage methods and ensure that all cans are sealed properly before being stored. Additionally, make sure all cans are stored at temperatures below 40°F (4°C). If you suspect that your canned goods have been exposed to temperatures above this threshold, then they should be discarded immediately.


Botulism in canned foods can be extremely dangerous if not identified early on. Knowing how to detect signs of contamination such as off smells or tastes, bulging cans, and compromised seals can help protect against consuming potentially deadly toxins produced by C. botulinum bacteria.