It can occur from eating home-canned goods of many types, and infants can contract it from eating raw honey. Botulism is a rare but serious foodborne disease. It is caused by contamination of certain foods by the botulism bacterium commonly found in the soil. An adult may become ill by eating spoiled food containing the botulism toxin. This toxin is produced when the bacteria grow in improperly canned foods and occasionally in contaminated fish.
Infant botulism is caused by eating the spores of the botulinum bacterium.
For infants one source of these spores is honey. When contaminated food is eaten by adults, toxin is absorbed from the intestines and attaches to the nerves causing the signs and symptoms of botulism. Early symptoms include blurred vision, dry mouth, difficulty in swallowing or speaking, general weakness, and shortness of breath. The illness may progress to complete paralysis, respiratory failure, and death. When infants eat contaminated food, the spores grow in the intestines and release toxin.