Chemical dehairing of bovine skin to reduce pathogenic bacteria and bacteria of fecal origin

A chemical dehairing process was applied to artificially contaminated bovine hide to evaluate the effect on populations of Escherichia coli O157:H7 and Salmonella Typhimurium, as well as other strains of E. coli, total coliforms, and aerobic plate counts (APC). Pieces of hide (4 cm(2)) were contaminated with bovine feces inoculated with both rifampicin-resistant E. coli O157:H7 and S. Typhimurium to yield a final count of each pathogen of ca. 5.0 log(10) CFU/cm(2), or with noninoculated feces which produced an approximate final APC of 6.0 log(10) CFU/cm(2) and a coliform and E. coli count of 5.0 log(10) CFU/cm(2). Counts of pathogens, APC, coliforms, and E. coli were conducted before and after applying the dehairing treatment. S. Typhimurium and E. coli O157:H7 populations were significantly reduced from initial numbers (5.1 to 5.3 log(10) CFU/cm(2)) to levels below the detection limit of 0.5 log(10) CFU/cm(2) after chemical dehairing. APC, coliforms, and E. coli counts were also reduced significantly after dehairing, with reductions of 3.4 for APC, 3.9 for coliforms, and >4.3 log(10) CFU/cm(2) for other E. coli strains. Since the hide is a major source of fecal contamination of beef carcass surfaces, chemical dehairing may be beneficial in reducing overall contamination of carcasses.