Food Microbiology
Clostridium botulinum
An anaerobic, spore-forming bacterium producing botulinum neurotoxin. Proteolytic types do not grow below pH 4.6, aw 0.94 or 10 °C.
The reason home-canned low-acid vegetables need a pressure canner, not just boiling water, and why a bulging or dented can is never opened.
Related terms
12D concept
Food MicrobiologyThe commercial sterility standard for low-acid canned food: a heat process delivering twelve decimal reductions of Clostridium botulinum spores.
Low-acid food
Food Safety & RegulationA food with an equilibrium pH above 4.6 and water activity above 0.85, capable of supporting Clostridium botulinum growth.
Water activity
Food ChemistryThe ratio of the vapour pressure of water in a food to the vapour pressure of pure water at the same temperature. It measures how much water is available for microbial growth and chemical reactions — not how much water is present.
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