Oscar T P
USDA, Agricultural Res Serv, Microbial Food Safety Research Unit and USDA/1890, Center for Food Science and Technol, Univ of Maryland Eastern Shore, Princess Anne, Maryland 21853, USA.
J Food Prot. 2009 Feb;72(2):304-14. doi: 10.4315/0362-028x-72.2.304.
To better predict risk of Salmonella infection from chicken subjected to temperature abuse, a study was undertaken to develop a predictive model for survival and growth of Salmonella Typhimurium DT104 on chicken skin with native flora. For model development, chicken skin portions (2.14 cm2) were inoculated with 0.85 log of Salmonella Typhimurium DT104 (ATCC 700408) and then stored at 5 to 50 degrees C for 8 h. Kinetic data from the storage trials were fit to a primary model to determine lag time (lamda), specific growth rate (micrro), and the 95% prediction interval (PI). Secondary models for lamda, mu, and PI as a function of storage temperature were developed and then combined with the primary model to create a tertiary model. Performance of the tertiary model was evaluated against dependent data, independent data for interpolation, and independent data for extrapolation to kosher chicken skin by using an acceptable prediction zone from -1 (fail-safe) to 0.5 (fail-dangerous) log per skin portion. Survival of Salmonella Typhimurium DT104 on chicken skin was observed during 8 h of storage at 5 to 20 degrees C and at 50 degrees C, whereas growth was observed from 25 to 45 degrees C and was optimal at 40 degrees C with a lamda of 2.5 h and a mu of 1.1 log/h. Variation of pathogen growth, as assessed by PI, increased in a nonlinear manner as a function of temperature and was greater for growth conditions than no-growth conditions. The percentage of acceptable prediction errors was 82.6% for dependent data, 83.7% for independent data for interpolation, and 81.6% for independent data for extrapolation to kosher skin, which all exceeded the performance criterion of 70% acceptable predictions. Thus, it was concluded that the tertiary model provided valid predictions for survival and growth of Salmonella Typhimurium DT104 from a low initial dose on both nonkosher and kosher chicken skin with native flora.
为了更好地预测遭受温度滥用的鸡肉感染沙门氏菌的风险，开展了一项研究，以建立鼠伤寒沙门氏菌DT104在带有天然菌群的鸡皮上存活和生长的预测模型。为了建立模型，将鸡皮部分（2.14平方厘米）接种0.85对数的鼠伤寒沙门氏菌DT104（ATCC 700408），然后在5至50摄氏度下储存8小时。将储存试验的动力学数据拟合到一个初级模型中，以确定延迟时间（λ）、比生长速率（μ）和95%预测区间（PI）。建立了作为储存温度函数的λ、μ和PI的二级模型，然后将其与初级模型相结合，创建了一个三级模型。通过使用每块鸡皮-1（故障安全）至0.5（故障危险）对数的可接受预测区间，针对相关数据、用于内插的独立数据以及用于外推至犹太洁食鸡皮的独立数据，评估了三级模型的性能。在5至20摄氏度和50摄氏度下储存8小时期间，观察到鼠伤寒沙门氏菌DT104在鸡皮上的存活情况，而在25至45摄氏度下观察到其生长情况，在40摄氏度时生长最佳，延迟时间为2.5小时，比生长速率为1.1对数/小时。通过PI评估的病原体生长变化随温度呈非线性增加，且生长条件下的变化大于无生长条件下的变化。相关数据的可接受预测误差百分比为82.6%，用于内插的独立数据为83.7%，用于外推至犹太洁食鸡皮的独立数据为81.6%，所有这些均超过了70%可接受预测的性能标准。因此，得出结论，三级模型为鼠伤寒沙门氏菌DT104在低初始剂量下在带有天然菌群的非犹太洁食和犹太洁食鸡皮上的存活和生长提供了有效的预测。
