Antimicrobial Efficacy of Peroxyacetic Acid Spray for Beef Carcasses and Cuts at Beef Processing Plants

The objective of this study was to assess the antimicrobial efficacy of peroxyacetic acid (PAA) for beef in processing facilities. Inactivation of a wildtype Escherichia coli strain by up to 400 ppm PAA in solutions with different organic loads was determined. The microbial efficacy of PAA was assessed at two commercial beef plants for carcasses and cuts during routine production. The wild type E. coli strain was reduced by >7 log CFU upon exposing to PAA for 15 s at >100 and 200 ppm in low and high organic load solutions, respectively. PAA spray significantly reduced coliforms and E. coli by 1.7-2.0 log units on carcasses artificially inoculated with fecal slurry at one plant, and reduced aerobes and coliforms by 1.7 and 1.0 log units on naturally contaminated carcasses at the other plant. The reduction by PAA spray of aerobes (p < 0.05) on artificially inoculated carcasses was <0.5 log. Significant and consistent reduction of aerobes and coliforms on cuts by PAA was observed for fat surface at both beef plants, but not for lean cut surface. However, fewer cuts sprayed with PAA were positive for E. coli, regardless of cut type, compared with those that were not sprayed. Taken together, PAA can be effective for reducing microbial contamination of beef carcasses and cuts in commercial practice.