Use of antimicrobial agents in a novel cattle washing system

Abstract

Antimicrobial agents, 0.5% L-lactic acid and 50 ppm chlorine, along with water wash treatments (single or double) were evaluated in a cattle washing system for their effectiveness in reducing Aerobic Plate Counts (APC), coliforms, generic Escherichia coli (E. coli), and the incidence of Salmonella at three locations (brisket, belly, and inside round) on live animals pre- and post-treatment. Log reductions indicated that at all three locations, microbiological counts increased post-treatment as compared to pre-treatment. However, at the brisket region, the lactic acid, chlorine, and double water wash treatments demonstrated fewer increases (P < 0.05) in APCs (-0.1, -0.1, and -0.3 log CFU/cm², respectively) than did the single water wash (-0.8 log CFU/cm²). No statistical differences (P > 0.05) were observed with coliforms or generic E. coli at any location. Incidence of Salmonella was greatest after the single water wash (72.2%) versus before (57.8%). The chlorine treatment did show a reduction in incidence (60.0% versus 55.6%). Although reductions in microbiological counts were not demonstrated through this research, the system appeared to decrease the amount of visible contamination on the hides of the animals. Reducing visible contaminants on the animal potentially improves the dressing process, which may impact microbial counts of beef carcasses.