What water activity is required for germination and outgrowth of Clostridium perfringens?

What water activity is required for germination and outgrowth of Clostridium perfringens?

• A. 0.85
• B. 0.97
• C. 0.93
• D. 0.90

Answer: (C)

Water activity measures how much free water is available for microbial processes. Clostridium perfringens needs a fairly moist environment to germinate from spores and then outgrow, with the minimum aw for this process around 0.93. So foods with an aw of about 0.93 or higher can permit spore germination and subsequent growth under the right conditions. Values well below this threshold keep water availability too limited for germination, while higher values also support growth, but the specific germination/outgrowth requirement is best described by 0.93.

Water activity measures how much free water is available for microbial processes. Clostridium perfringens needs a fairly moist environment to germinate from spores and then outgrow, with the minimum aw for this process around 0.93. So foods with an aw of about 0.93 or higher can permit spore germination and subsequent growth under the right conditions. Values well below this threshold keep water availability too limited for germination, while higher values also support growth, but the specific germination/outgrowth requirement is best described by 0.93.