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目的探讨克罗诺杆菌TaqMan-MGB探针实时荧光PCR在婴幼儿奶粉食品安全监测中的应用效果。方法制备克罗诺杆菌染菌量为1.5×100~106CFU/25g奶粉的样品,在增菌48 h内每隔4 h各取1 ml提取DNA,进行TaqMan-MGB探针实时荧光PCR,并在婴幼儿奶粉食品安全风险监测中应用,同步进行细菌分离、TaqMan探针实时荧光PCR(美国FDA推荐),比较3种方法的敏感性和符合率。结果 3种方法可检测到1.5 CFU/25 g奶粉染菌量样本所需增菌培养的时间不一样,TaqMan-MGB探针实时荧光PCR需18 h,美国FDA推荐的TaqMan探针实时荧光PCR需24 h,分离培养则需要36 h。TaqMan-MGB探针实时荧光PCR从293份样本的前增菌液中检出15份阳性,从77个可疑菌落中检出23个阳性菌落,鉴定结果与另2种方法一致。结论克罗诺杆菌TaqMan-MGB探针实时荧光PCR快速、特异、灵敏,可用于婴幼儿奶粉筛查和辅助鉴定,提高食品安全风险监测的速度和灵敏度。
Objective To investigate the effect of TaqMan-MGB probe real-time fluorescent PCR on the food safety monitoring of infant formula. Methods A sample of Cronobacter bacteria with a bacterial count of 1.5 × 100 ~ 106CFU / 25g was prepared and 1 ml DNA was extracted every 4 h in 48 h of enrichment for TaqMan-MGB probe real-time PCR. Application of milk powder food safety risk monitoring in infants and young children, simultaneous bacterial separation, TaqMan probe real-time PCR (FDA recommended), the sensitivity and compliance of the three methods were compared. Results The time required for enrichment culture of 1.5 CFU / 25 g milk powder samples by 3 methods was different. The real-time fluorescent PCR of TaqMan-MGB probe was 18 h. 24 h, separation and culture takes 36 h. Real-time PCR with TaqMan-MGB probe detected 15 positive samples from pre-added broth of 293 samples, and 23 positive colonies were detected from 77 suspicious colonies. The identification results were consistent with the other two methods. Conclusion The real-time fluorescent PCR of Cronobacterium TaqMan-MGB probe is rapid, specific and sensitive, and it can be used in screening and auxiliary identification of infant milk powder to improve the speed and sensitivity of food safety risk monitoring.