A simple and rapid realtime PCR assay for the detection of Shigella and Escherichia coli species in raw milk

作者：Wang, Yuexia; Zhao, Pengfei; Zhang, Huanling; Chen, Wanyi; Su, Xiaoyu; Suo, Biao^*

来源：Journal of Consumer Protection and Food Safety, 2013, 8(4): 313-319.

DOI：10.1007/s00003-013-0837-9

• Shigella
• Escherichia coli
• Duplex realtime PCR
• Detection

Escherichia coli and Shigella spp. are two major bacterial contaminants in raw milk. Effective screening of the two microbes before starting the production process is a critical step for the quality and safety guarantee of the resulting dairy products. This study reported a rapid and simple realtime PCR assay using a ubiquitous primer and probe set targeting the tuf gene for the detection of E. coli and Shigella spp. An internal amplification control (IAC) was also comprised to indicate false-negative results. The duplex realtime PCR assay showed a high efficiency above 96 % and a detection limit < 10 cfu per PCR. When artificially contaminated raw milk samples were further evaluated, the assay performed equally as well as the traditionally cultural-based method, and facilitated quantitative detection of the two microbes in the range from similar to 10(2) to similar to 10(6) cfu mL(-1) raw milk. The detection limit was similar to 10(2) cfu mL(-1) raw milk for either or a mixture of the two strains without pre-enrichment step, and could be < 10 cfu per 10 mL of raw milk if a pre-enrichment step was added. Considering the detection effectiveness, time-consumption saving, and economical efficiency, the present duplex realtime PCR assay has a great potential in the application in raw milk for assessing their microbiological quality and safety in relation to E. coli and Shigella spp.

• 出版日期2013-12
• 单位河南农业大学