COMPARISON OF STEAM PASTEURIZATION AND OTHER METHODS FOR REDUCTION OFPATHOGENS ON SURFACES OF FRESHLY SLAUGHTERED BEEF

The effectiveness of a recently invented ''steam pasteurization'' (S) process in reducing pathogenic bacterial populations on surfaces of fr eshly slaughtered beef was determined and compared with that of other standard commercial methods including knife trimming (T), water washin g (35 degrees C; W), hot water/steam vacuum spot cleaning (V), and spr aying with 2% vol/vol lactic acid (54 degrees C, pH 2.25; L). These de contamination treatments were tested individually and in combinations. Cutaneus trunci muscles from freshly slaughtered steers were inoculat ed With feces containing Listeria monocytogenes Scott A, Escherichia c oli O157:H7, and Salmonella typhimurium over a predesignated meat surf ace area, resulting in initial populations of ca. 5 log CFU/cm(2) of e ach pathogen. Tissue samples were excised from each portion before and after decontamination treatments, and mean population reductions were determined. Treatment combinations evaluated were the following (trea tment designations within the abbreviations indicate the order of appl ication): TW, TWS, WS, VW, VWS, TWLS, and VWLS. These combinations res ulted in reductions ranging from 3.5 to 5.3 log CFU/cm(2) in all three pathogen populations. The TW, TWS, WS, TWLS, and VWLS combinations we re equally effective (P > 0.05), resulting in reductions ranging from 4.2 to 5.3 log CFU/cm(2). When used individually, T, V, and S resulted in pathogen reductions ranging from 2.5 to 3.7 log CFU/cm(2). Steam p asteurization consistently provided numerically greater pathogen reduc tions than T or V. Treatments T, V, and S were all more effective than W which gave a reduction on the order of 1.0 log CFU/cm(2)). Steam pa steurization is an effective method for reducing pathogenic bacterial populations on surfaces of freshly slaughtered beef, with multiple dec ontamination procedures providing greatest overall reductions.