Ivanek Renata, Gröhn Yrjö T, Wiedmann Martin, Wells Martin T
Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
J Food Prot. 2004 Dec;67(12):2688-97. doi: 10.4315/0362-028x-67.12.2688.
Listeriosis is a foodborne disease caused by the bacterium Listeria monocytogenes. The food industry and government agencies devote considerable resources to reducing contamination of ready-to-eat foods with L. monocytogenes. Because inactivation treatments can effectively eliminate L. monocytogenes present on raw materials, postprocessing cross-contamination from the processing plant environment appears to be responsible for most L. monocytogenes food contamination events. An improved understanding of cross-contamination pathways is critical to preventing L. monocytogenes contamination. Therefore, a plant-specific mathematical model of L. monocytogenes cross-contamination was developed, which described the transmission of L. monocytogenes contamination among food, food contact surfaces, employees' gloves, and the environment. A smoked fish processing plant was used as a model system. The model estimated that 10.7% (5th and 95th percentile, 0.05% and 22.3%, respectively) of food products in a lot are likely to be contaminated with L. monocytogenes. Sensitivity analysis identified the most significant input parameters as the frequency with which employees' gloves contact food and food contact surfaces, and the frequency of changing gloves. Scenario analysis indicated that the greatest reduction of the within-lot prevalence of contaminated food products can be achieved if the raw material entering the plant is free of contamination. Zero contamination of food products in a lot was possible but rare. This model could be used in a risk assessment to quantify the potential public health benefits of in-plant control strategies to reduce cross-contamination.
李斯特菌病是一种由单核细胞增生李斯特菌引起的食源性疾病。食品行业和政府机构投入了大量资源来减少即食食品被单核细胞增生李斯特菌污染的情况。由于灭活处理可以有效消除原材料上存在的单核细胞增生李斯特菌，因此加工后来自加工厂环境的交叉污染似乎是大多数单核细胞增生李斯特菌食品污染事件的原因。更好地了解交叉污染途径对于预防单核细胞增生李斯特菌污染至关重要。因此，开发了一种特定工厂的单核细胞增生李斯特菌交叉污染数学模型，该模型描述了单核细胞增生李斯特菌污染在食品、食品接触表面、员工手套和环境之间的传播。一家烟熏鱼加工厂被用作模型系统。该模型估计，一批食品中有10.7%（第5和第95百分位数分别为0.05%和22.3%）可能被单核细胞增生李斯特菌污染。敏感性分析确定最显著的输入参数为员工手套接触食品和食品接触表面的频率以及更换手套的频率。情景分析表明，如果进入工厂的原材料没有污染，那么一批食品中受污染产品的厂内流行率可以最大程度降低。一批食品中产品零污染是可能的，但很罕见。该模型可用于风险评估，以量化厂内控制策略减少交叉污染对公共卫生的潜在益处。
