Purpose: The purpose of these studies was to comparatively evaluate the accuracy of the Atlas Salmonella SEN Detection Assay and the BAX Salmonella Assay for the detection of Salmonella enterica in carcass rinse samples from multiple processors.
Methods: Three poultry processors collected routine rinse samples according to USDA FSIS MLG 4.07 by rinsing each carcass with ~400 ml of Buffered Peptone Water (BPW). A 30 ± 0.6 ml post rinse aliquot was combined with 30 ± 0.6 ml of sterile BPW and enriched for 20-24 hours at 35° ± 2°C. Each sample was analyzed by Atlas, BAX, and culture methods. For the Atlas method, 400 µl of enrichment was transferred into transfer tubes. For the BAX method, 1.5-2 ml of enrichment was transferred into sterile cryovials and held at 4°C. Samples were processed at Roka on the Atlas according to the approved Atlas method and by culture according to MLG 4.07. Processors sampled paired enrichments for BAX analysis according to routine procedure. BAX results were disclosed after Atlas method and culture results were reported.
Results: The Atlas method reported 1 false negative, whereas the BAX method reported 9 false negative and 1 false positive results compared to culture. Percent agreement between culture and Atlas and BAX Salmonella assays were 99.31% and 93.06%, respectively. Processors A, B and C contributed 25.69, 27.78 and 46.53% of 144 samples. All discrepant results were attributed to the 25.69% of samples prepared by processor A.
Significance: Screening method performance and accuracy may be adversely impacted by the proficiency or complexity of operator handling requirements.