Changes in the Population of Clostridium perfringens Type A Frozen in a Meat Medium ¹

Survival of eight strains of Clostridium perfringens type A frozen in a meat medium at -23 C and held under aerobic conditions for 1,7, and 14 days was 17, 12, and 6.2%, respectively. Holding under anaerobic conditions for 1, 7, and 14 days gave survival percentages of 51, 26, and 10%, respectively. Survival was not affected by cooling rates of 0.5, 1.5, and 20 C per min. Addition of 10% sucrose to the meat medium did not affect survival. The meat medium with glycerol concentrations of 1.0 and 2.0 M gave survival percentages of 13, 63, 144, and 58, respectively, when frozen at -23 C and held for 22 to 24 h.