US Department of Agriculture, Agricultural Research Service, Chemical Residue and Predictive Microbiology Research Unit, Center for Food Science and Technology, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA.
J Food Prot. 2013 Jun;76(6):1035-40. doi: 10.4315/0362-028X.JFP-12-362.
The U.S. Department of Agriculture's tertiary Pathogen Modeling Program (PMP) model for survival and growth of Salmonella enterica ser. Typhimurium definitive type 104 (DT104) on chicken skin stored for 0 to 8 h at 5 to 50°C was evaluated for its ability to predict survival and growth of the same organism on chicken skin after frozen storage for 6 days at -20°C. Experimental design and methods used to collect data for model development (dependent data) were the same as those used to collect data for survival and growth after frozen storage (independent data for extrapolation). This was done to provide a valid comparison of observed and predicted values. The model was classified as providing acceptable predictions of the test data when the proportion of residuals in an acceptable prediction zone (pAPZ) from -1 log (fail-safe) to 0.5 log (fail-dangerous) was ≥0.7. The pAPZ for dependent data, independent data for interpolation, and independent data for extrapolation to a new independent variable of previous frozen storage were all acceptable (pAPZ ≥0.7), with the exception of the pAPZ for dependent data at 50°C, where an unacceptable pAPZ of 0.625 was obtained. Although a majority of observed log counts were less than predicted log counts, indicating that frozen storage of chicken skin for 6 days at -20°C had injured some Salmonella Typhimurium DT104, the injury was not large enough to cause the tertiary PMP model to provide unacceptable predictions. Thus, it was concluded that the tertiary PMP model provided valid predictions of survival and growth of Salmonella Typhimurium DT104 on chicken skin that had a previous history of frozen storage for 6 days at -20°C. Additional research is needed to determine how broadly the model can be applied to other conditions of previous frozen storage.
美国农业部三级病原体建模计划（PMP）模型预测在 5 至 50°C 下储存 0 至 8 小时的鸡皮上肠炎沙门氏菌血清型 Typhimurium 定型 104（DT104）的存活和生长情况，该模型适用于预测在 -20°C 下冷冻储存 6 天后鸡皮上相同生物体的存活和生长情况。用于收集模型开发数据的实验设计和方法（依赖数据）与用于收集冷冻储存后存活和生长数据的方法相同（外推的独立数据）。这样做是为了提供观察值和预测值的有效比较。当可接受预测区（pAPZ）中残留比例（-1 对数（安全失效）至 0.5 对数（危险失效））大于等于 0.7 时，模型被归类为可接受的测试数据预测。依赖数据的 pAPZ、插值的独立数据和外推到以前冷冻储存的新独立变量的独立数据均为可接受（pAPZ≥0.7），除了 50°C 时依赖数据的 pAPZ 不可接受，获得了 0.625 的不可接受 pAPZ。尽管大多数观察到的对数计数小于预测的对数计数，表明在 -20°C 下冷冻储存鸡皮 6 天已经损伤了一些肠炎沙门氏菌 Typhimurium DT104，但损伤不足以导致三级 PMP 模型提供不可接受的预测。因此，可以得出结论，三级 PMP 模型对之前在 -20°C 下冷冻储存 6 天的鸡皮上肠炎沙门氏菌 Typhimurium DT104 的存活和生长情况提供了有效的预测。需要进一步研究以确定该模型可以在多大程度上应用于其他以前冷冻储存的条件。
