摘要
对大肠杆菌O157:H7型菌株的各毒力基因及基因组中的特异序列进行了设计和比对,确定292bp的检测引物。常规定性PCR和实时定量PCR证明该引物特异性强。模拟样品的前增菌实验结果表明本方法可以在原样品活菌浓度约2.0CFU/mL时通过16h增菌后检测出来,总的检测时间可以控制在24h内。本实验建立的PCR方法可用于食品中大肠杆菌O157:H7的快速测定。
Genomic comparisons were carried out on Escherichia coli virulence genes and genome-specific sequences,which were located in the genomes of Escherichia coli serotype O157：H7 strains released in the GenBank.One pair of primers specific for ECs3032 genes was exploited for the amplification to give a 292 bp PCR product.Conventional qualitative PCR and real-time quantitative PCR assays showed higher specificity of the primers.The assays were used for detecting Escherichia coli O157：H7 in ground beef initially inoculated at the dosages of 2,20,or 200 CFU/mL after 2,11,16 h and 20 h of enrichment at 37 ℃ in modified EC broth.Escherichia coli O157：H7 was detected in all samples inoculated.The whole detection procedure was finished within 24 hours with a sensitivity of 2.0 CFU/mg beef sample using the PCR assay established in this study.Thus,an effective method is provided for the rapid PCR detection of Escherichia coli in foods.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2010年第8期212-215,共4页
Food Science
基金
上海市质量监督检验局项目(2007-21)
关键词
大肠杆菌O157:H7
食源性致病菌
特异序列
PCR
enterohemorrhagic Escherichia coli O157：H7
foodborne pathogenic bacteria
specific sequence
PCR
