Purpose: The objective of this study was to evaluate the capability of the alternative method without enrichment for rinsates and short 5.5 h enrichment for ground product to detect Salmonella spp. at a threshold level of > 2.0 CFU/ml in rinsates and > 2 log CFU/325 g in ground product.
Methods: Rinsates from surface inoculated chicken thighs and ground turkey from a poultry processing plant were inoculated using standard method validation procedures. Five samples of each matrix served as uninoculated, negative controls. In addition, 231 production rinsates and 140 ground turkey samples were tested with the alternative method.
Results: The alternative method screened all 20 inoculated rinses and ground products as presumptive. The MPN estimate of Salmonella levels for the inoculated rinse samples ranged from 24 CFU/ml to > 110 CFU/ml and 58.5 CFU/325g to 17,875 CFU/325g for the ground product. All samples confirmed as positive for Salmonella following the reference method. Of the 231 side-by-side rinsate samples, 5 samples were presumptive with the alternative method but did not culturally confirm (2%). Of the 140 ground poultry samples, 10 samples were presumptive with the alternative method, of which 5 did not confirm (3.5%).
Significance: The Bio-Rad iQ-Check Salmonella II standard protocol with modifications of testing 1.5 ml of sample and shortened 5.5-h enrichment for ground product is as effective as the USDA-FSIS MLG 4.07, MLG 4C.05, and MLG Appendices 2.03 methods at detecting Salmonella in unenriched rinsates when recovered at a level of at least 2 log CFU/ml.