Growth of Clostridium perfringens from spore inocula in sous-vide turkey products

Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag ground turkey (pH 6) that included 0.3% (ww) sodium pyrophosphate, and sodium chloride at 0, 1, 2 or 3% (ww). The packages were processed to an internal temperature of 71.1 °C, ice chilled and stored at various temperatures. The total C. perfringens population was determined by plating diluted samples on tryptose-sulfite-cycloserine agar followed by anaerobic incubation at 37 °C for 48 h. At 28 °C, the addition of 3% salt in turkey was effective in delaying growth for 12 h. At 15 °C, growth occurred at a relatively slow rate in the presence of 1–2% salt. Vegetative cells were not observed even after 28 days of storage in the presence of 3% salt. C. perfringens growth was not observed at 4 °C regardless of salt levels. The D-values ranged from 23.2 min (no salt) to 17.7 min (3% salt). Cyclic and static temperature abuse of refrigerated products for 8 h did not lead to growth by C. perfringens from a spore inoculum.