蔬菜中大肠杆菌的快速检测方法

ON ENZYME-SUBSTRATE METHOD FOR RAPID DETECTION OF FECAL COLIFORM BACTERIA IN RAW VEGETABLES

蔬莱中埃希氏大肠杆菌的酶-底物快速检测法，以FCM培养液中添加MUG作为与埃希氏菌在培养过程中生成的β-葡萄糖苷酸酶反应的底物，埃希氏菌则作为蔬菜提取物样品加入培养液中．阳性结果系根据MUG被酶作用后的水解产物在3650A紫外线照射下所产生的蓝色荧光反应．培养物中MUG的合适剂量为50μg／mL，获得阳性结果时间不超过24h，本法与传统的多管发酵法比较结果表明，在检测粪源性污染的蔬菜样品时，它的敏感性及准确性与多管发酵法相一致。

A simple enzyme-substrate method for rapid detection of Escherichia coli in raw vegetables is established. In this method,MUG is used as substrate and added into the FCM medium for causing a reaction with β-glucuronsidase which is produced by E. coil in the process of incubation. The coliform bacteria (E. coil)are eluted from vegetables with saline and the samples of eluate are taken and added into the medium. Positive results are based on the hydrolysis product of MUG which can emit blue fluorescence under 3 650 A UV illumination. The appropriate dosage of MUG in culture is equal to 50μg/mL,and the culture time for getting positive results is less than 24 hours. According to the results of comparative studies of this method with the traditional multiple-tube fermentation (MTF) method for detection of fecal coliform bacteria in vegetables, it is demonstrated that the enzymesubstrate method is as sensitive and accurate as the MTF method.