Purpose: To was to determine the reduction of Salmonella on inoculated Moab (knuckle) bones under simulated industry conditions.
Methods: Bones (n=10/rep) were full submersed into a Salmonella cocktail (Salmonella Heidelburg, Salmonella Typhimurium, and Salmonella Enteritidis) for 2 min, then set onto racks in the cooler for 30 min to allow for Salmonella attachment to occur. One sample was pulled to determine concentration on pre-treated bones. Bones were placed into a pre-heated Enviropak™ Minipak series commercial oven at 195°F for 240 h (10 d). One sample was pulled for analysis at the following time points: 24 h, 2, 4, 6, 8, and 10 d. The experiment was performed in duplicate. Serial dilutions were made and plated onto XLT4 agar with a thin TSA overlay. Plates were incubated at 37°C for 24 - 48 h then counted to determine surviving populations. Counts were converted to log CFU/bone prior to statistical analysis. Samples with no growth after 48 h of incubation were considered negative for Salmonella.
Results: The drying cycle reduced Salmonella populations by approximately 7.6 log CFU/bone after 24 h of drying, which is a significant (P < 0.05) reduction. All samples taken after 24 h of drying were negative for Salmonella ssp.
Significance: This validation of Moab bone processing demonstrates that a 7.0 log CFU/bone reduction can be achieved using a drying cycle of 195°F for 10 d. When this cycle is used within the plant, it would be effective in eliminating Salmonella ssp. The validation of these process steps are an important practice to fulfill the more rigorous requirements being developed for pet food regulations.