Purpose: (1) To demonstrate PIPER’s ability to successfully detect Salmonella Typhimurium in commercial poultry rinsate samples with only a 6-hour enrichment. (2) To enumerate spiked concentrations of the same pathogen in these samples with no enrichment.
Methods: The poultry sample (300 g) was rinsed with buffered peptone water (BPW) media (60 ml). For enumeration experiments, rinsate aliquots were spiked with serial dilutions of viable Salmonella Typhimurium (n = 6 for each concentration) and analyzed on PIPER (75 mins for 11 simultaneous tests per instrument). For enrichment experiments, poultry rinsate (20 ml) was mixed with BPW (20 ml) and spiked with 0 and 3 CFU of Salmonella Typhimurium. After 6 hours of enrichment, aliquots of each culture (n = 5 each) were analyzed on PIPER and compared to selective media plating.
Results: Both enriched and non-enriched samples achieved 100% relative correlation to selective plating. Following the enrichment period, positive samples were distinguished from negative samples with ~30 ppm false positive and false negative error rates (0.9999 tolerance intervals, alpha = 0.05). Without enrichment, PIPER successfully detected Salmonella Typhimurium and showed good linearity over a dynamic range of 5 orders of magnitude (R2 = 0.93). All Salmonella Typhimurium concentrations were discriminated with a confidence of 0.995 (alpha = 0.005).
Significance: The PIPER platform could have significant impact in food safety industry with the demonstrated ability to successfully enumerate a common foodborne pathogen in a complex matrix within 75 minutes, and detect its presence within a single work shift.