Enumeration of Clostridium perfringens in Foods

HPB Method MFHPB-23
November 2001

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1. APPLICATION

This method is applicable to the enumeration of viable Clostridium perfringens in foods to determine compliance with the requirements of Sections 4 and 7 of the Food and Drugs Act. This revised method replaces MFHPB-23, dated September 1997.

2. DESCRIPTION

This method has been shown to produce satisfactory results with naturally-contaminated meat and poultry products (8.2-8.4).

3. PRINCIPLE

The procedure estimates the number of viable Clostridium perfringens per g or mL of food. A portion of the product is mixed and incubated with a selective medium by the pour plate technique. Typical black colonies are counted as presumptive Clostridium perfringens. A minimum of five of these colonies are subjected to confirmatory tests. The number of confirmed Clostridium perfringens is calculated from the ratio of presumptive colonies confirmed to presumptive colonies tested.

4. DEFINITION OF TERMS

See Appendix A of Volume 2.

5. COLLECTION OF SAMPLES

See Appendix B of Volume 2.

6. MATERIALS AND SPECIAL EQUIPMENT

The following media and reagents (1-3) are commercially available and are to be prepared and sterilized according to the manufacturer's instructions. See also Appendix G of Volume 2 and reference 8.1 for the formula of individual media.

1) Sulfite cycloserine agar (SC) (originally designated as Egg yolk free tryptose sulfite cycloserine agar)