Horizontal method for the enumeration of Clostridium perfringens - Colony-count technique
ISO 7937 (2004) method: Clostridium perfringens
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1 Quantitative process control with CRM-CP
- Use a quantitative reference material (CRM-CP) with a known number of Clostridium perfringens.
- Defrost the material at room temperature for 30 minutes.
- Mix well before use and dilute the material so countable numbers are inoculated on the media (TSC (SC)) by spread plate method.
- Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
- Incubate at (37 ± 1) °C for (20 ± 2) h.
- Count the colony forming units and register in a control chart.
- The characteristic reaction is: Black colonies.
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2 Quantitative process control with RM-CP veg
- Use a quantitative reference material (RM-CP veg) with a known number of Clostridium perfringens.
- Defrost the material at room temperature for 30 minutes.
- Mix well before use and dilute the material so countable numbers are inoculated on the media (TSC (SC)) by spread plate method.
- Best results are obtained when a practicable range of 80 cfu to 120 cfu per plate with a minimum number of 50 cfu per plate is used.
- Incubate at (37 ± 1) °C for (20 ± 2) h.
- Count the colony forming units and register in a control chart.
- The characteristic reaction is: Black colonies.

Best Practice
The single strain CRM-CP contains Clostridium perfringens spores which are not heat-resistant. This material can only be used for vegetative cell analyse

Best Practice
The single strain RM-CP veg contains Clostridium perfringens vegetative cells and heat-resistant spores. This material can be used for vegetative cell analyse and the spore analyse