신선편이 엽채류의 병원성 E. coli 검출을 위한 생화학적동정법 비교 분석

Abstract

The objective of this study was to isolate pathogenic Escherichia coli from fresh vegetables with selective media and Petrifilm, and identify a suspicious colony using biochemical identification. Twenty gram of lettuce, twenty gram of cabbage and ten gram of sprout were prepared, and a 5-strain mixture of pathogenic E. coli (Enterohemorrhagic E. coli NCCP11142, Enterotoxigenic E. coli NCCP14037, Enteropathogenic E. coli NCCP14038, Enteroaggregative E. coli NCCP14039, Enteropathogenic E. coli NCCP15661) was inoculated to obtain 1, 2 and 3 log CFU/g. Eighty to ninety milliliter of buffered peptone water (BPW) was placed and pummeled for 60 s. As a results, the Petrifilm method was all positive, but enrichment method of qualitative analysis was negative except for 3-log CFU/g inoculated lettuce. Regarding biochemical identification of pathogenic E. coli, the identification rates were dependent on type of methods and vegetables; lettuce: API 20E 100% (44/44), Microgen GNA 100% (44/44) and Food System 66.7% (10/15), cabbage: API 20E 64.7% (22/34), Microgen GNA 50% (16/32) and Food System 60% (9/15), sprout: API 20E 65.1% (28/43), Microgen GNA 62.3% (27/43) and Food System 53.3% (8/15). These results could be useful in determining an appropriate method to detect pathogenic E. coli in fresh vegetables.