Reduction of Microorganisms on Beef Surfaces with Electricity and Acetic Acid ^‡

This study determined the effect of a 2% acetic acid spray, pulsed-power electricity, pulsed-power electricity with a spray of sterile deionized water, and a combination of acetic acid spray and pulsed-power electricity in reducing the pathogens Escherichia coli O157 and Salmonella typhimurium and aerobic plate counts on beefsteaks compared to an inoculated control. Ten steaks per treatment were inoculated with 1 ml of E. coli O157 (l0⁵ CFU/ml) or S. typhimurium (10⁵ CFU/ml) for 2 min and then subjected to one of the five treatments. Acetic acid spray and acetic acid spray and pulsed-power electricity treatments significantly (P < .05) reduced the incidence of Escherichia coli O157 compared to inoculated controls and produced a 1-log CFU/cm² reduction in the incidence of S. typhimurium . Ten steaks per treatment were also inoculated with 1 ml of S. typhimurium (l0⁵ CFU/ml) for 2 min, treated with acetic acid spray, pulsed-power electricity and a sterile deionized water spray, or acetic acid spray and pulsed-power electricity and stored in an incubator at -2°C for 48 h to stimulate chill-cooler conditions in the beef industry. Acetic acid spray with and without pulsed-power electricity caused a 1-log CFU/cm² reduction in S. typhimurium . These data indicate a need for the use of both 2% acetic acid and pulsed-power electricity in packing-house facilities to help achieve the goal of improved microbiological safety of beef.