Rapid anaerobic recovery and enumeration of Clostridium perfringens from food using the Fung Double Tube method

Abstract

The goal of this project is to demonstrate that the Fung double tube method is a viable technique for recovering and enumerating anaerobic bacteria such as Clostridium perfringens from food systems like ground beef. The small anaerobic environment and the ability to enumerate the bacteria are the primary benefits of using the Fung double tube method. Ground beef was artificially inoculated with Clostridium perfringens to act as the contaminated sample, and dilutions of this sample were inoculated within modified TSN medium/double tubes. The samples required seven days to incubate for colony counts. A heat shock was added along with an enrichment step that utilized BHI broth to show that this method also allows for the recovery of heat-injured anaerobic bacteria from food. There was a significant difference between recovering nonstressed Clostridium perfringens and heat stressed Clostridium perfringens (p<0.05) with counts of nonstressed Clostridium perfringens reaching 5.0x107 CFU. However, there was not a significant difference between recovering heat stressed Clostridium perfringens and heat stressed Clostridium perfringens with an enrichment (p>0.05).