Uhlig Elisabeth, Olsson Crister, He Jiayi, Stark Therese, Sadowska Zuzanna, Molin Göran, Ahrné Siv, Alsanius Beatrix, Håkansson Åsa
Department of Food Technology, Engineering and Nutrition Lund University Lund Sweden.
Department of Biosystems and Technology Swedish University of Agricultural Sciences Alnarp Sweden.
Food Sci Nutr. 2017 Sep 20;5(6):1215-1220. doi: 10.1002/fsn3.514. eCollection 2017 Nov.
Customer demands for fresh salads are increasing, but leafy green vegetables have also been linked to food-borne illness due to pathogens such as O157:H7. As a safety measure, consumers often wash leafy vegetables in water before consumption. In this study, we analyzed the efficiency of household washing to reduce the bacterial content. Romaine lettuce and ready-to-eat mixed salad were washed several times in flowing water at different rates and by immersing the leaves in water. Lettuce was also inoculated with before washing. Only washing in a high flow rate (8 L/min) resulted in statistically significant reductions ( < .05), "Total aerobic count" was reduced by 80%, and count was reduced by 68% after the first rinse. The number of contaminating was not significantly reduced. The dominating part of the culturable microbiota of the washed lettuce was identified by rRNA 16S sequencing of randomly picked colonies. The majority belonged to , but isolates from and were also frequently found. This study shows the inefficiency of tap water washing methods available for the consumer when it comes to removal of bacteria from lettuce. Even after washing, the lettuce contained high levels of bacteria that in a high dose and under certain circumstances may constitute a health risk.
消费者对新鲜沙拉的需求不断增加，但绿叶蔬菜也与诸如O157:H7等病原体引起的食源性疾病有关。作为一项安全措施，消费者通常在食用前用水清洗绿叶蔬菜。在本研究中，我们分析了家庭清洗降低细菌含量的效率。将长叶生菜和即食混合沙拉以不同流速在流动水中冲洗数次，并将叶片浸入水中。生菜在清洗前还接种了[此处原文缺失接种物相关内容]。只有以高流速（8升/分钟）冲洗才导致统计学上的显著减少（P<0.05），第一次冲洗后“总需氧菌数”减少了80%，[此处原文缺失相关细菌名称]菌数减少了68%。污染的[此处原文缺失相关细菌名称]数量没有显著减少。通过对随机挑选菌落的rRNA 16S测序确定了清洗后生菜可培养微生物群的主要部分。大多数属于[此处原文缺失相关菌群名称]，但也经常发现来自[此处原文缺失相关菌群名称]和[此处原文缺失相关菌群名称]的分离株。这项研究表明，就从生菜中去除细菌而言，消费者可用的自来水清洗方法效率低下。即使清洗后，生菜仍含有大量细菌，在高剂量且在某些情况下可能构成健康风险。
