非预增菌可视化快速检测食品中肠毒素大肠杆菌K88的研究

摘要

本研究运用肠毒素大肠杆菌K88(E.coli K88)特异的适配体结合纳米金和银增强技术,建立了E.coli K88一种可视化快速检测技术,实现约2 h检测E.coli K88达10 CFU/反应的灵敏度.通过人工模拟E.coli K88污染25 g蔬菜、牛奶或猪肉等食品原料,采用该可视化快速检测技术进行非预增菌直接检测,结果显示检测灵敏度达100 CFU/mL(或g),检测需时约2 h,在1.0×102 ~1.0×105 CFU/mL(或g)的E.coli K88污染浓度范围内,样品A630nm吸光值与目标菌污染浓度对数值呈线性关系,相关系数R2 0.97以上.研究结果表明,E.coli K88可视化检测方法可用于食品样品E.coli K88污染非预增菌的快速、灵敏检测分析.%An aptamer recognition combined with nanogold labeling with silver staining(AGS)system was developed for the rapid visual detection of enterotoxigenic Escherichia coli K88(E.coli K88,the sensitivity of the detection of E.coli K88 reached 10 CFU/reaction.The method was used to detect E.coli K88 without enrichment in infected food,including 25 g of vegetables,milk and pork food with various numbers of E.coli K88 CFU.The lowest level of DNA consistently detected by the AGS was 102 CFU/mL(or CFU/g),the entire assay could be completed in 2 h.Standard curves were generated between the log of number of CFU/ml(g)of E.coli K88 and the A630 nm values from the AGS assays,with coefficients of determination[R2] over 0.97,indicating that the AGS showed adequate quantification capability for detection of bacferia in food.In conclusion,the AGS could be used for sensitive,rapid and quantitative detection of E.coli K88 in food without enrichment.