Evaluation of peroxyacetic acid as a potential pre-grinding treatment for control of Escherichia coli O157:H7 and Salmonella Typhimurium on beef trimmings

Peroxyacetic acid was evaluated in four separate trials for ability to reduce populations of Escherichia coli O157:H7 and Salmonella serotype Typhimurium on fresh beef trim. Trial 1 examined the effectiveness of peroxyacetic acid on individual pieces of fresh beef trim. Trial 2 evaluated the efficacy of peroxyacetic acid at low levels of contamination on batches of fresh beef trim. Trial 3 studied a washing effect of water. Lastly, Trial 4 compared the effectiveness of peroxyacetic acid to lactic acid. At various inoculation levels, peroxyacetic acid reduced populations of both pathogens by approximately 1.0 log10 CFU/cm2 on fresh beef trim. Trial 3 showed that approximately half of the reductions found in Trials 1 and 2 were due to a washing effect of the water dip. In addition, as shown in Trial 1, increases in concentrations (>200 ppm) did not significantly increase log10 reductions of both pathogens. Following a water dip in Trial 4, peroxyacetic acid caused a reduction of 0.7 log10 CFU/cm2 in E. coli O157:H7 and 1.0 log10 CFU/cm2 in Salmonella Typhimurium, whereas lactic acid caused a reduction of 1.3 log10 CFU/cm2 in E. coli O157:H7 and 2.1 log10 CFU/cm2 in S. Typhimurium following the water dip. These results show that peroxyacetic acid was not more effective than 2% l-lactic acid in reducing pathogens on fresh beef trim.