Purpose: The objective of this study was to test the ability of a PCR/MS assay to detect and identify foodborne bacteria in spiked and naturally contaminated food products.
Methods: Both spiked food samples and foods collected during the regulatory process were analyzed with the assay. After pre-enrichment and selective enrichment incubations, DNA was extracted directly from the broth and analyzed on the assay. Limits of detection and sensitivity in the presence and absence of background microflora were determined for different pathogens.
Results: Salmonella was detected in 9 of 10 culture-positive selective enrichment broths from naturally contaminated samples. The serovar identified by serology was a match to PCR/MS results in 8 of 10 samples. Analysis of pre-enrichment broth was less successful in the analysis of both naturally contaminated and spiked foods where the correct serovar was identified in 29 of 48 spiked samples (60%). Serovar-level identification of Salmonella was performed with as little as 80 pg of DNA (pure sample).
Significance: The development of rapid bacterial pathogen detection and identification assays will improve response times to public health events. This work indicates that PCR/MS could be a vital tool for quickly assessing possible vehicles in foodborne pathogen outbreaks.