Which organism causes botulism from improperly canned foods?

• A. Bacteroides fragilis
• B. Clostridium botulinum
• C. Clostridium perfringens
• D. Clostridium septicum

Answer: (B)

Botulism from improperly canned foods comes from the botulinum toxin produced by Clostridium botulinum. This bacterium is anaerobic and forms spores that can survive inadequate canning. In a sealed, low-acid can, these spores can germinate and release the potent neurotoxin, which blocks the release of acetylcholine at neuromuscular junctions. That disruption leads to flaccid paralysis and can progress to respiratory failure, making properly controlled canning temperatures and acidity essential to prevent toxin production.

The other organisms listed do not cause this toxin-mediated foodborne illness. Bacteroides fragilis is an anaerobic gut bacterium associated with intra-abdominal infections; Clostridium perfringens causes food poisoning via a different toxin but not botulinum toxin; Clostridium septicum is linked to gas gangrene and systemic infections rather than botulism.