Introduction: The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) collects samples from cattle, swine, and poultry (chicken and turkey) slaughter and/or grinding establishments as part of the process verification programs. These samples are analyzed for the presence of Salmonella and all positive samples are further subtyped/serotyped.
Purpose: To analyze results from FSIS sampling programs in order to identify possible trends in the data, including changes in the percentage of positive samples and serotype information over time.
Methods: Samples were collected from FSIS-regulated slaughter and/or grinding establishments and were analyzed by using the FSIS Microbiology Laboratory Guidebook methods described in Chapter 4.05 and 4C.03 for screening, identification, and isolation of Salmonella.
Results: Data sets from March 1998 to November 2011 were used to identify trends in percentage of samples positive for Salmonella and to compare the most common serotypes found in the different product categories (cattle, swine, chicken, or turkey). Generally, all products showed a reduction in percentage of positive samples over this 13-year period. A comparison of the percentage of positive carcass and ground product samples identified higher levels of Salmonella detected in ground product. Additionally, serotype differences between species slaughtered and product types (carcass sponge/rinse versus ground meat sample) were found.
Significance: FSIS sampling programs show reductions in the percentage of samples positive for Salmonella for all product categories analyzed. Notably, turkey products, specifically the percentage of positive carcass samples, had the largest decrease since 2006, when FSIS turkey carcass sampling began. Data analyses also found a higher percentage of Salmonella-positive ground product samples compared to carcass samples for all product categories.