TEN HOUR REAL-TIME PCR TECHNIQUE FOR DETECTION OF SALMONELLA IN READY-TO-EAT MEATS

Authors: Patel, Jitu; Bhagwat, Arvind

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/3/2006
Publication Date: 6/26/2006
Citation: Patel, J.R., Bhagwat, A.A. 2006. Ten hour real-time PCR technique for detection of Salmonella in ready-to-eat meats [abstract]. Institute of Food Technologists Annual Meeting Book of Abstracts. Paper No. 036-09. June 24-28, 2006, Orlando, Florida.

Interpretive Summary:

Technical Abstract: Real-time Polymerase chain reaction (PCR) assays were evaluated to detect Salmonella in ready-to-eat (RTE) meats following 8 h of pre-enrichment. The sensitivity and accuracy of Molecular beacon and TaqMan probe PCR assays were compared with the conventional USDA microbiological procedure using artificially contaminated RTE meats. Fluorescent probes targeting invasion-related genes specifically detected invA gene (TaqMan probe) and iagA gene (Molecular beacon probe) from Salmonella spp. RTE meats (turkey, ham, and bologna) were artificially contaminated with Salmonella enterica serovar Typhimurium at the estimated level of 2 to 4 cells per 25 g. After 20 h of pre-enrichment in the buffered-peptone water, both protocols were sensitive enough to identify all positive samples. Further, all inoculated RTE meat samples (n=35) were detected by Molecular beacon-based PCR assay after 8 h of pre-enrichment. However, only 23 of 35 samples were detected by TaqMan assay following 8 h pre-enrichment. Similarly, all uninoculated controls (n=12) were negative by both PCR assays and USDA procedure. Molecular beacon PCR assay can detect as low as 2 to 4 cfu of Salmonella in 25 g RTE meats within 10 hours. Developing rapid pathogen detection methods with shorter pre-enrichment times and real-time data monitoring capabilities will expedite food borne outbreak investigations.