Department of Food and Animal Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea.
Int J Food Microbiol. 2011 Jan 31;145(1):287-92. doi: 10.1016/j.ijfoodmicro.2011.01.010. Epub 2011 Jan 12.
This study was performed to compare the effectiveness of individual treatments (ultrasound and organic acids) and their combination on reducing foodborne pathogens on organic fresh lettuce. Lettuce leaves were inoculated with a cocktail of three strains each of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes and treated with ultrasound (40 kHz) alone, organic acids (0.3, 0.5, 0.7, 1.0, and 2.0%--malic acid, lactic acid, and citric acid) alone and combined with ultrasound and organic acids for 5 min. For all 3 pathogens, the combined treatment of ultrasound and organic acids resulted in additional 0.8 to 1.0 log reduction compared to individual treatments, without causing significant quality change (color and texture) on lettuce during 7 day storage. The maximum reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes were 2.75, 3.18, and 2.87 log CFU/g observed after combined treatment with ultrasound and 2% organic acid for 5 min, respectively. Our results suggest that the combined treatment of ultrasound with organic acids was effective at increasing pathogen reduction compared to individual treatments without significantly affecting quality, and demonstrates its potential as a novel method to increase the microbial safety on organic fresh lettuce.
本研究旨在比较单独处理（超声和有机酸）及其组合对减少有机新鲜生菜食源性病原体的效果。将三种菌株（大肠杆菌 O157:H7、鼠伤寒沙门氏菌和单核细胞增生李斯特菌）的混合物接种到生菜叶片上，并用超声（40 kHz）、有机酸（0.3、0.5、0.7、1.0 和 2.0% - 苹果酸、乳酸和柠檬酸）单独处理或联合处理 5 分钟。对于所有 3 种病原体，与单独处理相比，超声和有机酸联合处理可额外减少 0.8 到 1.0 个对数减少，在 7 天储存期间不会对生菜的质量（颜色和质地）造成显著变化。在联合处理 5 分钟后，超声和 2%有机酸的组合处理可使大肠杆菌 O157:H7、鼠伤寒沙门氏菌和单核细胞增生李斯特菌的最大减少量分别达到 2.75、3.18 和 2.87 log CFU/g。我们的结果表明，与单独处理相比，超声与有机酸联合处理可更有效地增加病原体减少，而不会显著影响质量，并证明其作为增加有机新鲜生菜微生物安全性的一种新方法具有潜力。
