INTERACTIVE EFFECTS OF TEMPERATURE, INITIAL PH, SODIUM-CHLORIDE, AND SODIUM PYROPHOSPHATE ON THE GROWTH-KINETICS OF CLOSTRIDIUM-PERFRINGENS

The interactive effects of temperature (12 to 42 degrees C), initial p H (5.5 to 7), sodium chloride (0 to 3%) and sodium pyrophosphate conce ntrations (0 to 0.3%) on the growth in Trypticase-peptone-glucose-yeas t extract broth of a three-strain mixture of Clostridium perfringens v egetative cells were determined. The number of viable C. perfringens c ells was determined at appropriate intervals by plating on tryptose-su lfite-cycloserine agar. Growth data were analyzed by the Gompertz equa tion; the gompertz B and M parameters were then used to calculate lag- phase duration, exponential growth rate, generation time, and maximum population-density values. The data indicated that the growth kinetics of C. perfringens were dependent on the interaction of the four varia bles, particularly in regard to exponential growth rates and lag-phase durations. Cubic models based on the natural logarithm transformation of lag-phase duration and generation time were evaluated and appeared to adequately fit the data. The data suggest that sodium pyrophosphat e can have significant bacteriostatic activity against C. perfringens and may provide processed meats with a degree of protection against th is microorganism, particularly if employed in conjunction with a combi nation of acidic pH, high salt concentrations, and adequate refrigerat ion.