Clostridium botulinum is a rod-shaped, anaerobic (meaning it lives and grows in low oxygen conditions), spore-forming (meaning it is able to survive for years in the environment) bacteria. It produces a potent neurotoxin responsible for causing botulism. This neurotoxin is one of the most toxic substances known; even very small amounts can cause illness or death.
Temperature is a critical factor in the multiplication of C. botulinum in the environment, and outbreaks are more likely to take place during the summer and fall seasons, when ambient temperature is high. C. botulinum has a minimum growth temperature of 15°C (60°F). Although it grows best at temperatures between 30°C (86°F) and 40°C (104°F).
Anywhere where there has been raw sewage discharge and deaths of terrestrial and aquatic invertebrates and fish posses an increased risk of botulism. Maggots can also pose a risk because they are able to harbor the toxin in their bodies. In water, it requires a pH between 5.1 and 5.4 to grow.