Purpose: To determine the how well the Assurance Salmonella VIP and TPSG can detect Salmonella in various foods, including spinach, chicken rinses, dry pet food, ground chicken, beef trim, almonds, ice cream and raw eggs; using a proprietary enrichment media (mEHEC, BioControl Systems) with novobiocin incubated for 20 - 24 h.
Methods: Various 25-g food samples were inoculated with low levels (1 - 5 CFU/sample) of Salmonella cultures that had been grown in BHI overnight, then diluted to 100 CFU/ml in BPBD and stored at 2 - 8°C for 24 h prior to sample inoculation. The samples were enriched in 225 ml of the mEHEC + novobiocin for 20 - 24 hours at 42°C. The samples were tested using the Assurance Salmonella Gold VIP and Transia Plate Salmonella Gold ELISA. The enrichment broths were transferred to RVS and incubated an additional 20 h at 42°C. These samples were streaked onto XLD plates for confirmation.
Results: Positive results were obtained from 81/82 inoculated samples with both VIP and TPSG assays. The one negative sample was also confirmed as negative from the XLD plate. All uninoculated control samples yielded negative test results.
Significance: This study demonstrates that food samples inoculated with low levels of Salmonella and enriched in mEHEC + novobiocin for 20 - 24 h at 42°C are reliably detected with VIP and TPSG, yielding results equivalent to plate confirmation.