Monday, May 24, 2010

Purifying bacterial DNA from contaminated food samples

Contaminated food is becoming an increasing bacteria are the most common cause of food-borne illnesses. Lambertz et al. at the National Food Administration in Finland describe a sensitive and specific real-time PCR assay to detect the food-borne pathogen Yersinia pseudotuberculosis. Traditional culture-based methods are limited by the low isolation rate of this Gram-negative bacterium in naturally contaminated samples.  Using the MasterPure™ Complete DNA and RNA Purification Kit, the researchers isolated DNA from 25 food samples including mixed salad, minced meat, nonpasteurized milk, carrots, turnips, cabbage, lettuce, onion, pumpkin, and tomatoes. They developed TaqMan® qPCR assays using gene-specific probes to detect the Y. pseudotuberculosis ail gene, and distinguish it from related Y. enterocolitica serotypes. Whereas 6 of the analyzed food samples were positive for Y. pseudotuberculosis as indicated by PCR, all 25 were negative when analyzed by the traditional culture method.

ResearchBlogging.orgLambertz, S. et al. (2008). TaqMan-Based Real-Time PCR Method for Detection of Yersinia pseudotuberculosis in Food Applied and Environmental Microbiology, 74 (20), 6465-6469 DOI: 10.1128/AEM.01459-08

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