Effect of Acetic Acid on the Death Rates at 52°C of Salmonella newport, Salmonella typhimurium and Campylobacter jejuni in Poultry Scald Water

Abstract

The D₅₂ values [time necessary for a one log decrease in bacterial numbers at 52°C (125.6°F)] were determined for Salmonella newport, Salmonella typhimurium and Campylobacter jejuni in water that had been taken from the scald tank of a large-scale poultry slaughter operation, sterilized and then treated with various concentrations of acetic acid. The addition of 0.1% acetic acid to the scald water drastically reduced the D₅₂ values for all three bacteria; that of S. newport dropped from 22.18 ± 2.68 min to 2.88 ± 0.20 min; S. typhimurium from 29.05 ± 5.61 min to 3.56 ± 0.28 min; and C. jejuni from 5.97 ± 0.93 min to 1.20 ± 0.45 min. When the acetic acid concentration was increased to 0.2%, the D₅₂ values of S. newport and S. typhimurium were 0.92 ± 0.16 and 1.30 ± 0.16 min, respectively. Addition of 1% acetic acid caused instantaneous bacterial death and D₅₂ values could not be calculated. This suggests that addition of the GRAS compound, acetic acid, to poultry scald water shows promise as a means of destroying Salmonella and Campylobacter in the scald tank and thereby reducing cross-contamination. Since the scald tank is the first step in poultry processing, a reduction at this critical control point might also reduce dissemination of Salmonella and Campylobacter during subsequent processing steps. Plant trials are being planned.