Purpose: To validate novel alternative methods for detecting both Salmonella spp. and Listeria spp. in environmental samples from one enriched sponge using UPB.
Methods: Stainless steel surfaces were spiked with a cocktail of Listeria monocytogenes and Salmonella Typhimurium, from which one set of sponges were enriched in UPB and compared to sponges that were enriched with BPW for Salmonella spp. and sponges enriched with UVM for Listeria spp. UPB enrichments were analyzed by the phage based next day detection methods and 48h immunoassay detection methods. The UPB methods were compared to AOAC-approved BPW and UVM 48h enrichment methods.
Results: For Listeria detection; from the UPB enrichment, the phage-based assay detected16 positives out of 30 spiked samples, the 48 h immunoassay detected 15 of 30 spiked samples compared to 12 out of 30 spikes samples for the AOAC-UVM/VIDAS approved 48h method. For Salmonella detection; from the UPB enrichment , the phage based assay detected14 positives out of 30 spiked samples, the 48h immunoassay detected 15 of 30 spiked samples compared to 16 out of 30 spikes samples for the AOAC-BPW/VIDAS approved 48 h method. The UPB enriched detection methods were statistically equivalent to both AOAC-approved single enrichment methods.
Significance: The VIDAS® UP Salmonella (SPT) and VIDAS® UP Listeria (LPT) next day detection methods from a single UPB enriched sponge were equivalent to the 48h enrichment methods for detecting Salmonella spp. and Listeria spp. from stainless steel surfaces.