Clostridium botulinum are rod-shaped bacteria (also called C. botulinum. They are anaerobic, meaning they live and grow in low oxygen conditions. The bacteria form protective spores when conditions for survival are poor. C. botulinum is responsible for a disease called botulism. Botulism is a life-threatening disease caused by the ingestion of a potent neurotoxin produced during growth of the C. botulinum bacteria. This neurotoxin is among the most toxic substances known; even microscopic amounts can cause illness or death.

A neurotoxin is a poisonous chemical that affects the central nervous system. It can destroy, paralyze, or adversely affect nerves or nerve tissue. C. botulinum produces seven different types of neurotoxins designated by the letters A through G; only types A, B, E, and F cause illness in humans. C. botulinum spores are often found on the surfaces of fruits and vegetables and in seafood. The organism grows best under low-oxygen conditions and produces spores and toxins. The toxin is most commonly formed when food is improperly processed (canned) at home. C. botulinum cannot grow below a pH of 4.6, so acidic foods, such as most fruits, tomatoes, and pickles, can be safely processed in a water bath canner. However, foods with a higher pH (most vegetables and meats) must be processed under pressure. Therefo-re, a pressure cooker should be used. The pressure cooker will reach high-enough temperatures to destroy the C. botulinum spores.

The classic symptoms of botulism can include vomiting, diarrhea, double vision, blurred vision, drooping eyelids, slurred speech, difficulty swallowing, dry mouth, and trouble walking. Sometimes people might look like they are drunk. If untreated, a person who is sick with botulism can stop breathing and die. How soon do symptoms appear? Symptoms of botulism usually appear 12–36 hours after eating food that contains toxin, but can occur as early as 6 hours or as late as 10 days.