Abstract The purpose of this research was to characterize Listeria monocytogenes from several environmental and clinical sources and assess the efficacy of single and combined physico-chemical treatments in reducing biofilm on lettuce leaves. PCR analysis of L. monocytogenes isolates collected from different clinical (10 strains) and environmental sources (12 strains) was used to look for the presence of one Listeria-specific gene and five virulence genes. Biofilms of L. monocytogenes were developed on lettuce leaves over 24 h. A 5-min ultrasound and a 300-ppm sodium hypochlorite (NaOCl) wash resulted in similar reductions in cell numbers of 0.82 log CFU cm−2. For chlorine dioxide (ClO2) at 60 ppm, the cell numbers were reduced by ∼5.45 log CFU cm−2. A combined treatment of 5 min of ultrasound plus 300 ppm NaOCl or 40 ppm ClO2, provided maximal efficacy, reducing the number of L. monocytogenes on the lettuce surface to non-detectable levels. Therefore, ClO2 has the potential to replace NaOCl for the disinfection of food products in the food industry.

中文翻译：

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物理化学处理对减少生菜叶片表面单核细胞增生李斯特菌生物膜的影响

摘要 本研究的目的是表征来自多种环境和临床来源的单核细胞增生李斯特菌，并评估单一和联合物理化学处理在减少生菜叶片生物膜方面的功效。从不同临床（10 株）和环境来源（12 株）收集的单核细胞增生李斯特菌分离株的 PCR 分析用于寻找一种李斯特菌特异性基因和五种毒力基因的存在。单核细胞增生李斯特菌的生物膜在生菜叶上形成超过 24 小时。5 分钟超声和 300 ppm 次氯酸钠 (NaOCl) 洗涤导致细胞数量类似减少 0.82 log CFU cm-2。对于 60 ppm 的二氧化氯 (ClO2)，细胞数量减少了约 5.45 log CFU cm-2。5 分钟超声波加 300 ppm NaOCl 或 40 ppm ClO2 的组合处理，提供最大功效，将生菜表面上单核细胞增生李斯特氏菌的数量减少到不可检测的水平。因此，在食品工业中，ClO2 具有替代 NaOCl 用于食品消毒的潜力。