Generation Times and Modeling of Enterotoxin-Positive and Enterotoxin-Negative Strains of Clostridium perfringens in...

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. The rapid growth of the ent⁺ strains between 41 and 46°C underlines previous recommendations for proper holding and cooling of protein foods such as meat and poultry known to support the growth of this organism.