USDA/ARS/ERRC, Wyndmoor, Pennsylvania 19038, USA.
Foodborne Pathog Dis. 2010 Feb;7(2):153-7. doi: 10.1089/fpd.2009.0405.
We conducted stabilization studies to determine the ability of Clostridium perfringens spores to germinate and grow during exponential cooling of a commercial formulation of pork scrapple. Scrapple was inoculated with a mixture of three strains of C. perfringens spores (NTCC 8238, NCTC 8239, and ATCC 10288), vacuum packaged, and reheated (20 min/93.3 degrees C) in a circulating water bath. The cooked samples were cooled (30 s) in an ice bath before being transferred to a programmable water bath to cool through the temperature range of 54.4 degrees C to 7.2 degrees C in 12, 14, or 21 h to simulate deviations from the required cooling time of 6.5 h. After cooling, the samples, in duplicate, were analyzed to determine if growth from spores had occurred. The samples were plated onto tryptose-sulfite-cycloserine agar and incubated anaerobically at 37 degrees C for 48 h before counting the colonies. Minimal growth (less than 1.0 log) was observed during a 12- or 14 h cooling period. However, when the time to achieve 7.2 degrees C was extended to 21 h, C. perfringens spores germinated and grew from an inoculum of approximately 3.0 log(10) to approximately 7.8 log(10) CFU/g. Thus, scrapple must be cooled after cooking to 7.2 degrees C within 6.5 h, but for no more than 14 h, to prevent a food safety hazard from outgrowth of C. perfringens spores during cooling.
我们进行了稳定性研究，以确定梭状芽孢杆菌孢子在商业猪肉香肠制剂的指数冷却过程中发芽和生长的能力。香肠接种了三种梭状芽孢杆菌孢子（NTCC 8238、NCTC 8239 和 ATCC 10288）的混合物，真空包装，并在循环水浴中重新加热（20 分钟/93.3 摄氏度）。煮熟的样品在冰浴中冷却（30 秒），然后转移到可编程水浴中，通过 12、14 或 21 小时将温度从 54.4 摄氏度降至 7.2 摄氏度，以模拟偏离所需冷却时间 6.5 小时的情况。冷却后，将样品一式两份进行分析，以确定是否发生了孢子的生长。将样品平板接种于三糖硫酸盐环丝氨酸琼脂上，在 37 摄氏度下厌氧培养 48 小时，然后计数菌落。在 12 或 14 小时的冷却期内观察到最小生长（少于 1.0 对数）。然而，当达到 7.2 摄氏度的时间延长至 21 小时时，梭状芽孢杆菌孢子从约 3.0 对数（10）的接种物中发芽并生长至约 7.8 对数（10）CFU/g。因此，香肠在烹饪后必须在 6.5 小时内冷却至 7.2 摄氏度，但不得超过 14 小时，以防止在冷却过程中梭状芽孢杆菌孢子的过度生长带来食品安全隐患。
