Beef Carcass Washing to Reduce Bacterial Contamination

Abstract

Ninety-six market beef forequarters were washed with water chlorinated at 200 ppm, to determine the effects of wash water temperature, pH in the acidic range, and spray pressure on reduction of total aerobic bacteria. Samples were taken before wash, 45 min. and 24 hr. after wash. Reduction in total counts were evident 45 min. and 24 hr. after washing, but the magnitude of the reduction in bacterial numbers was greater after 24 hours. Average log reductions in count for two tests were 1.5191 and 2.3097 when sampled 45 min. after wash and 2.3901 and 3.0716, respectively, when sampled 24 hr. after wash. Reductions in log counts were maximum at pH 6 and 7. Lowering the pH to 4 or 5 with acetic acid decreased the effectiveness of the wash. A high-pressure wash at 24.6 kg/cm² was more effective than a wash at 4.2 kg/cm². After 24 hr. the average log reduction for low pressure was 2.1476, and for high pressure, 3.3140. Wash water at 51.7 C yielded an average log reduction of 3.2017 compared to 2.2600 for tap water at 12.8 C. The effects of pH and wash water temperature were overshadowed by the effectiveness of high-pressure washing, wherein the treatment frequently resulted in a reduction of the bacterial numbers to less than two per square centimeter. Copyright © 1974. American Society of Animal Science . Copyright 1974 by American Society of Animal Science.