Real-time PCR Detection of Salmonella Species in Highly Inoculated 325-g Samples of Ground Turkey with a Reduced Enrichment Volume and Shortened Time-to-Result

Introduction: The natural occurrence of Salmonella in poultry and the global increase in ground turkey consumption poses a significant impact on consumer contamination risk. As a result, the poultry industry is under higher scrutiny to reduce contamination in ground product. Current testing programs for raw poultry are cost prohibitive largely due to the sample size (325 g); therefore, establishments are looking to reduce costs by decreasing the 1,625 ml enrichment volume and shortening the time-to-result.

Purpose: The purpose of this study was to assess the ability of a real-time PCR assay to detect Salmonella using a reduced enrichment volume for highly inoculated 325-g samples of ground turkey for a shortened time-to-result.

Methods: Six different Salmonella serovars prevalent in poultry were selected to highly inoculate 325g samples of 85% (n=30) and 93% (n=30) lean ground turkey at a concentration of 10 CFU/g. After holding spiked product for 8-10 hours at 4°C, samples were homogenized with 975 ml of pre-warmed (46°C) BPW and incubated at 42°C for 4-10 hours. All samples were analyzed with the DuPont BAX System Real-Time PCR Assay for Salmonella and confirmed according to the USDA-FSIS reference culture method.

Results: For both 85% and 93% lean ground turkey samples, real-time PCR detected all positive results (n=60) after 6 hours of enrichment for all Salmonella serovars consistent with the reference culture method.

Significance: The results of this study provide establishments with a cost savings benefit by using a reduced enrichment method compared to the USDA-FSIS enrichment method of 1,625 ml to quickly determine status of contamination.