Genus of spore forming bacteria. Clostridium Botulinum is the most heat resistant of food-poisoning organisms; its growth is inhibited at pH 4.6 and below, thus it is only a problem in low-acid foods. Produces an endotoxin, botulina, highly toxic in minute doses, but destroyed by heat. Destruction of this organism is generally accepted as the minimum standard of processing for low-acid and medium-acid canned food, although other Clostridia are more heat-resistant.