Effect of Rising Temperatures on Growth and Survival of Clostridium perfringens Indigenous to Raw Beef ¹

Growth and survival of Clostridium perfringens indigenous to raw beef were compared to that of a composite of eight strains of C. perfringens inoculated into raw ground beef round, beef-round strips, and beef-round cores. A constantly rising temperature rate of 6 C/h and a dynamic rising temperature rate, predetermined from long time-low temperature (LTLT) oven beef cookery processes, were used to evaluate growth and survival. Survivors of C. perfringens were observed in raw ground beef and autoclaved ground beef at temperatures between 59 and 63 C. Growth in raw ground beef was more rapid than in raw beef-round strips. Raw ground beef supported growth of the indigenous flora to a greater extent than did autoclaved ground beef inoculated with the composite. The populations in raw, domestic frozen beef rounds used in commercial cooking processes were low, ranging from < 70/g to 1000/g, and varied among lots.