Peroxyacetic Acid Effectiveness against Salmonella on Raw Poultry Parts Is Not Affected by Organic Matter

Organic matter (OM) accumulation is common in chill tanks used to decontaminate raw poultry parts during processing. OM negatively affects the antimicrobial activity of chlorine-based compounds, but its effect on the antimicrobial effectiveness of peroxyacetic acid (PAA) on poultry meat has not been described. Therefore, this study evaluated the effect of OM on the efficacy of PAA solutions in simulated postchill tanks to reduce Salmonella artificially inoculated onto chicken parts. Chicken thighs were inoculated with a five-strain cocktail of poultry-borne Salmonella enterica serovars at ca. 6 log CFU/mL. Then, the thighs were immersed for 30 or 45 s in PAA solutions (500 or 1,000 ppm) with chicken slurry to simulate OM accumulation (0, 15, or 30 g/L). The thighs were rinsed with neutralizing buffered peptone water (100 mL), and rinsates were plated onto xylose lysine desoxycholate agar. Experiments were performed in triplicate (three thighs per treatment per replicate). Chemical oxygen demand, total nitrogen, and pH were measured as the water quality parameters of the PAA solutions before and after use. Chemical oxygen demand ranged from 2,905 mg/L in unused 500-ppm solutions without added OM to 6,290 mg/L in used 1,000-ppm solutions with 30 g/L OM. Initial total nitrogen was 42.5 +/- 2.0 and 60.9 +/- 8.3 mg/L for 15 and 30 g/L OM, which increased by 27 +/- 17 mg/L after use. The pH of solutions ranged from 3.16 +/- 0.14 to 3.42 +/- 0.09 for the 1,000-ppm solutions and from 3.59 +/- 0.06 to 3.96 +/- 0.06 for the 500-ppm solutions. Mean Salmonella reductions were 0.9 +/- 0.1 log CFU/mL of rinsate for the 500-ppm PAA treatment and 1.1 +/- 0.1 log CFU/mL of rinsate for 1,000-ppm PAA treatment. Exposure time did not have a significant effect on the logarithmic reductions. There was no significant effect of OM concentration (P > 0.05) on the reductions, indicating that the antimicrobial efficacy was not affected and that PAA solutions may continue to be reused as long as the PAA concentration is actively monitored.

Automated summary

The study evaluated the impact of organic matter on the efficacy of PAA solutions in reducing artificially inoculated Salmonella on chicken parts. Results showed that immersion of chicken thighs in PAA solutions could effectively reduce the presence of Salmonella, regardless of exposure time and OM concentration.