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As the beef industry evaluates intervention technologies to assure safe beef products, of interest are methods to reduce the microbial levels on raw beef trimmings destined for use as fresh ground beef.
This study evaluated a new system, the “radiant wall oven” (RWO), which exposes foods to radiant heat from a red-hot wall at 1000 to 1500°F. Radiant heat raises surface temperatures to levels sufficient to destroy targeted microorganisms without cooking the meat. This project evaluated the feasibility of using RWO heating to reduce populations of pathogens (e.g., Salmonella spp., including S. typhimurium DT 104) and Listeria monocytogenes on raw beef trimmings.
Targeted pathogens were inoculated onto beef trimmings and treated with variations in (1) RWO temperatures (1000 to 1500°F), (2) exposure times (3 to 5 sec.), and (3) antimicrobial spray pre-treatments (sodium lactate, acetic acid, citric acid and lactic acid at levels of 2, 3 and 5% of each). Levels of viable Salmonella and Listeria were determined before and after treatments.
The RWO treatment at 1300°F, when used in combination with pretreatment of 5% citric or acetic acids, reduced Salmonella spp. and Listeria monocytogenes populations on beef trimmings by 1.0-1.5 log cycles, while retaining the uncooked appearance of the meat. It was estimated that the surface temperature of the post-treated trimmings was 198°F, somewhat above the D-values (i.e., temperature required to reduce microbial load by one log cycle) for Salmonella and Listeria.