Fresh leafy greens like lettuce can be consumed raw and are susceptible to food-borne pathogens if they become contaminated. Recently, the number of reported pathogenic foodborne outbreaks related to leafy greens has increased. Therefore, it is important to try to alleviate the human health burden associated with these outbreaks. Processing of fresh-cut lettuce, including washing, is a step in the supply chain that needs to be well controlled to avoid cross-contamination. Current measures to control the quality of lettuce during washing include the use of chemicals like chlorine; however, questions regarding the safety of chlorine have prompted research for alternative solutions with peracetic acid (PAA). This study evaluates the effectiveness of a PAA (c.a. 75 mg/L) solution on the reduction of a commensal E. coli strain during the washing of fresh-cut lettuce. Experiments were performed at the laboratory scale and validated at the industrial scale. We observed that the use of PAA was not adversely affected by the organic load in the water. The contact time and dose of the PAA showed to be relevant factors, as observed by the approximately 5-log reduction of E. coli in the water. Results showed that once introduced during washing, E. coli remained attached to the lettuce, thus supporting the need to control for pathogenic bacteria earlier in the supply chain (e.g., during primary production) as well as during washing. Moreover, our results showed that the use of PAA during washing did not have an apparent effect on the levels of fluorescent pseudomonads (FP) and total heterotrophic bacteria (THB) in lettuce. Overall, our results at the laboratory and industrial-scales confirmed that during the processing of fresh-cut produce, where the accumulation of soil, debris, and other plant exudates can negatively affect washing, the use of a PAA (c.a. 75 mg/L) solution was an effective and safe wash water disinfectant that can potentially be used at the industrial-scale.

生菜等新鲜绿叶蔬菜可以生吃，如果受到污染，很容易受到食源性病原体的感染。最近，与绿叶蔬菜相关的致病性食源性疫情的报告数量有所增加。因此，努力减轻与这些疫情相关的人类健康负担非常重要。鲜切生菜的加工（包括清洗）是供应链中的一个步骤，需要良好控制以避免交叉污染。目前控制生菜质量的措施包括使用氯等化学物质；然而，有关氯安全性的问题促使人们研究过氧乙酸 (PAA) 替代解决方案。本研究评估了 PAA（约 75 毫克/升）溶液在鲜切生菜清洗过程中减少共生大肠杆菌菌株的有效性。实验在实验室规模进行，并在工业规模进行验证。我们观察到 PAA 的使用并未受到水中有机负荷的不利影响。根据水中大肠杆菌减少约 5 个对数的观察结果，PAA 的接触时间和剂量被证明是相关因素。结果表明，一旦在清洗过程中引入，大肠杆菌就会仍然附着在生菜上，因此支持在供应链早期（例如，初级生产期间）以及清洗过程中控制病原菌的必要性。此外，我们的结果表明，清洗过程中使用 PAA 对生菜中荧光假单胞菌 (FP) 和总异养细菌 (THB) 的水平没有明显影响。 总体而言，我们在实验室和工业规模上的结果证实，在鲜切农产品的加工过程中，土壤、碎片和其他植物分泌物的积累会对清洗产生负面影响，使用 PAA（约 75 毫克/升） ）溶液是一种有效且安全的洗涤水消毒剂，可用于工业规模。