Fresh produce shall be thoroughly washed at the retail level prior to serving to the consumer with potable water. Foodborne pathogens if present on a product may transfer to the wash water and cross-contaminate other products immersed in the water. Typically, an entire carton of lettuce (24 heads) is washed together increasing the likelihood of cross-contamination due to the close contact between each head. This study aimed to compare the effects of two wash batch volumes - "low" (8 heads) and "high" (24 heads) on the efficacy of two commercial water antimicrobials and cross-contamination. Red leaf lettuce was spot-inoculated (~5.0 log CFU/g) with Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes. In the first batch of washing, inoculated lettuce was washed with non-inoculated lettuce, followed by reuse of the water/antimicrobials twice washing only non-inoculated lettuce. Samples of inoculated and non-inoculated lettuce were collected to determine aerobic plate count (APC) as well as the populations of STEC and L. monocytogenes. Microbiological analysis of the wash water was also conducted. Wash volume (8 versus 24 lettuce heads) had limited effects on the antimicrobial activities of the interventions evaluated. Instead, high-volume wash increased the rate of cross-contamination between non-inoculated and inoculated lettuce, and cross-contamination of non-inoculated lettuce through wash water reuse. Retailers should consider volume of product processed per batch, reuse of wash water, and use of an appropriate water antimicrobial in consideration of mitigating potential product cross-contamination.

中文翻译：

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产品体积对生菜零售批量清洗过程中水抗菌功效和交叉污染的影响。


新鲜农产品在用饮用水提供给消费者之前应在零售层面进行彻底清洗。如果产品上存在食源性病原体，则可能会转移到洗涤水中并交叉污染浸入水中的其他产品。通常，一整箱生菜（24 个头）一起清洗，由于每个头之间的紧密接触，增加了交叉污染的可能性。本研究旨在比较两种洗涤批次体积（“低”（8 个头）和“高”（24 个头））对两种商用水抗菌剂功效和交叉污染的影响。用产生志贺毒素的大肠杆菌 (STEC) 和单核细胞增生李斯特菌对红叶生菜进行点接种（~5.0 log CFU/g）。在第一批洗涤中，将接种的生菜与未接种的生菜一起洗涤，然后重复使用水/抗微生物剂两次，仅洗涤未接种的生菜。收集接种和未接种的生菜样品以确定需氧平板计数 (APC) 以及 STEC 和单核细胞增生李斯特菌的数量。还对洗涤水进行了微生物分析。清洗量（8 个生菜头与 24 个生菜头）对所评估的干预措施的抗菌活性影响有限。相反，大量洗涤增加了未接种生菜和接种生菜之间的交叉污染率，以及通过洗涤水的重复使用而导致未接种生菜的交叉污染。零售商应考虑每批次处理的产品量、洗涤水的重复利用以及适当的水抗菌剂的使用，以减少潜在的产品交叉污染。