부산대학교 도서관

The efficacy of a 24-h Salmonellareal-time, or quantitative, PCR (qPCR) detection method was assessed through a collaborative effort involving eight Federal and state laboratories. Eleven foods including mashed potatoes, soft cheese, chili powder, chocolate, eggs, sprouts, apple juice, fish, shrimp, ground beef, and ground chicken were tested. For each food, seven blind samples were distributed to each participant for testing. These included six samples equivalently inoculated with 1 to 5 CFU/25 g of various serotypes of Salmonella(Gaminara, Weltevreden, Heidelberg, Senftenberg, Enteritidis, Newport, Typhimurium, and Kentucky for each food) and 10 to 50 CFU/25 g of the competitor Enterobacter cloacae. The seventh sample was inoculated with 10 to 50 CFU/25 g of the competitor, E. cloacae, only. These samples were tested for Salmonellaby using four methods in parallel: (i) 24-h qPCR method detecting Salmonellafrom modified buffered peptone water enrichment medium; (ii) 48-h qPCR method detecting Salmonellafrom a secondary selective enrichment broth; (iii) modified Bacteriological Analytical Manualmethod; and (iv) VIDAS, an immunoassay system. The results of the statistical analysis showed there was no significant (P≥ 0.05) difference between either of the qPCR methods and the modified Bacteriological Analytical Manualmethod for 10 of 11 foods. For the one exception, sprouts, detection by qPCR required 48 h. Both qPCR methods showed a detection limit of 0.08 to 0.2 CFU/g. These results provide a solid basis for using this 24-h qPCR rapid screening method to detect Salmonellain foods.