Purpose: The purpose of this study was to verify performance of the Atlas® Salmonella G2 (SG2) Detection Assay on additional produce matrices not previously submitted for AOAC-RI validation.
Methods: Produce matrices evaluated were spinach, iceberg lettuce, red leaf lettuce, fresh blueberries and scallions. For each matrix, six 25 g samples and one 375 g sample were prepared and inoculated with ~ 8 CFU/sample of Salmonella Newport (Cornell S5-436), and six 25 g samples were prepared as uninoculated matrix controls. All samples were enriched with Universal Pre-enrichment Broth (UPB) at a 1:9 sample to media ratio and incubated at 42 ± 2°C for 10 and 24 hours. Samples were collected at 10 and 24 hours according to the assay product insert and loaded onto the Atlas instrument. All samples collected at 24 hours underwent culture confirmation according to the FDA BAM Chapter 5 reference method.
Results: The Atlas method specifically detected Salmonella enterica in all inoculated samples at 10 and 24 hours and were culture confirmed. All uninoculated samples were negative according to the Atlas method at 10 and 24 hours and culture at 24 hours.
Significance: The Atlas method was verified for the propagation and detection of Salmonella enterica in five additional produce matrices using a 10 hour enrichment and total time to result of 13.5 hours with no false positive, false negative or inhibited results. The results substantiate the efficiency and accuracy of the assay on foods outside the current AOAC-RI approved matrices.