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Title: A rapid and simple DNA extraction procedure to detect Salmonella spp. and Listeria monocytogenes from fresh produce using real-time PCR

Author
item CHUA, TRINA - NGEE ANN POLYT,SINGAPORE
item Bhagwat, Arvind

Submitted to: Journal of Food Analytical Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2008
Publication Date: 6/3/2009
Citation: Chua, T., Bhagwat, A.A. 2009. A rapid and simple DNA extraction procedure to detect Salmonella spp. and Listeria monocytogenes from fresh produce using real-time PCR. Journal of Food Analytical Methods. 2:96-101.

Interpretive Summary: Current methods used to detect human pathogens such as Salmonella sp. and Listeria monocytogenes present in various foods require at least 2 to 3 days and up to 1 week. Because of the short shelf-life of ready-to-eat foods and fresh produce, faster methods to detect the presence of human pathogens are needed. In this study, we describe a simple and rapid procedure to detect human pathogens using cutting edge biotechnology. This new procedure can be performed under field conditions and has the distinct advantages of simplicity, biosafety, sample stability and compatibility with high throughput analyses. Rapid detection of food-borne pathogens is a crucial step in keeping fruits, vegetables, and other ready-to-eat foods safe. Both the food industry and consumers will benefit from the results of this research.

Technical Abstract: DNA isolation procedures significantly influence the outcome of PCR-based detection of human pathogens. Unlike clinical samples, DNA isolation from food samples such as fresh and fresh-cut produce has remained a formidable task and has hampered the sensitivity and accuracy of molecular methods. We optimized a commercially available FTA filter-based DNA isolation method in conjunction with real-time PCR-based detection of Salmonella spp. and Listeria monocytogenes from artificially inoculated fresh produce. Detection of 4 to 7 cells per 25 g of produce was consistently achieved with distinct advantages of easy sample preparation, stability and transport of DNA to the laboratory and biosafety. This DNA preparation protocol was rapid, sensitive, required minimal handling and reduced interference from produce-associated inhibitors of PCR.