食品中热损伤沙门氏菌选择性增菌及实时荧光聚合酶链式反应检测

摘要

为了能够高效检测食品中的亚致死损伤沙门氏菌,首先采用热激胁迫的方法得到亚致死损伤沙门氏菌细胞,进而基于选择性增菌培养液SEL建立一种实时荧光聚合酶链式反应检测技术。结果表明：在SEL中经过20h增菌培养后,无论是否经过修复培养,1～2CFU/5mL SEL的亚致死损伤细胞都能得到完全修复并增菌至109CFU/mL水平;依此建立的实时荧光聚合酶链式反应检测技术的纯菌扩增效率为95.41%,检测限为4CFU/反应体系,在人工污染碎食品样品中的检测限为3CFU/10g碎牛肉,而且与传统培养检测方法的结果相吻合。本方法在24h内即可完成食品中热损伤沙门氏菌的修复、选择性增菌以及实时荧光聚合酶链式反应检测,可应用于食品中沙门氏菌污染状况调查及高效检测。%A selective enrichment broth, SEL based real time PCR assay was established after treating a sublethal injured Salmonella cells by heat-shock. The results showed that 1-2 CFU of injured Salmonella cells in 5 mL SEL could be fully recovered and enriched to the level of l09 CFU/mL after a 20 h enrichment step even without the nonselective recovery process. The amplification efficiency of real time PCR was 95.41% and the detection limit was 4 CFU/reaction for Salmonella genomic DNA. The detection limit in artificially contaminated food sample was 3 CFU/10 g ground beef, and showed a high coincidence to the detection result by traditional culture-based assay. The overall recovery, selective enrichment and detection procedure of thermal injured Salmonella could be accomplished in 24 h, which showed a high potential of application in the effective detection of Salmonella in food.