| Method |
The growth of two enterotoxin-positive (ent+) and two enterotoxin-negative (ent-) strains of Clostridium perfringens were examined in two laboratory media, fluid thioglycollate and fluid thioglycollate with beef, and in autoclaved ground beef stored at 37, 41, 43, 46, and 48°C. There was no association between enterotoxigenicity and optimum growth temperature, which varied depending on strain and medium. Experimentally obtained values for generation times at 43°C were as low as 8.7 and 6.3 min in thioglycollate both for ent+ and ent- strains respectively. In autoclaved ground beef the shortest generation times, 7.1 min and 9.2 min, were obtained at 41 and 46°C for two ent+ strains. For ent- strains in autoclaved ground beef a generation time of 6.6 min was observed at 43°C. Temperature optima obtained experimentally were the same as those obtained by the Gompertz model (For Gompertz model see: Buchanan, R. 1991. 'Using spreadsheet software for predictive micro-biology applications' J. Food Safety 11:123-134 AND Whiting, R. and R. Buchanan. 1994. Microbial Modeling. Food Technol. 48: 113-120). |