ISO 7937 - Enumeration of Clostridium perfringens

ISO 7937: Microbiology of food and animal feding stuffs — Horizontal method for the enumeration of Clostridium perfringens — Colony-count technique

The ISO 7937 standard includes a horizontal method for the enumeration of viable Clostridium perfringens on products intended for human consumption and animal feeding, and on environmental samples in food production and food processing.

The definition of Clostridium perfringens within the scope of ISO 7937 standard is bacteria that form characteristic colonies (black precipitate formed by reduction of sulfide to sulfide, black precipitate that stains colonies black) in the specified selective medium and give positive confirmatory reactions when the test is performed by either of them.

Principle of Analysis
• Petri dishes are inoculated with a certain amount of test sample if the starting product is liquid, or with a certain amount of starting suspension in the case of other products. Other plates are inoculated using decimal dilutions of the test sample or initial suspension under the same conditions.
• Plates are incubated anaerobically at 37 °C for 20 hours ± 2 hours.
• The number of characteristic colonies is verified and the sample is incubated. The number of C. perfringens is calculated per milliliter or gram.

You can contact Nanolab Food Analysis Laboratory for "Clostridium perfringens Count" in food and feed.