Neutral pH sodium chlorite decreases recovery of Campylobacter in neutralizing buffered peptone water from simulated broiler carcass rinses

Abstract

ABSTRACTThe goal of this study was to evaluate factors causing low recovery of Campylobacter during regulatory sampling following acidified sodium chlorite (ASC) treatment of broiler carcasses and subsequent carry‐over into neutralizing buffered peptone water (nBPW) rinses. Solution alkalinity was shown to positively correlate with the presence of un‐reduced chlorite anion in the recovery broth, implying that low recovery of Campylobacter from rinses may be due to residual chlorite, an oxidizing agent. To demonstrate the susceptibility of Campylobacter to residual chlorite, three strains were inoculated into pH = 7.5 nBPW with or without addition of sodium chlorite and stored for 24 hr at 4 °C prior to culturing. Microbial counts from the solutions indicated that residual chlorite can decrease recovery by up to 4 log CFU/mL relative to controls. Acceptable recovery of Campylobacter from nBPW rinses containing residual chlorite may require development of a suitable neutralizing agent in the nBPW recovery medium.Practical applicationsRecovery of viable Campylobacter spp. from broiler carcasses following antimicrobial treatment with acidified sodium chlorite may potentially be compromised when using nBPW as the recovery medium. At neutral or slightly alkaline pH, residual sodium chlorite, an oxidizing species, is not reduced by thiosulfate present in nBPW, and demonstrates antimicrobial effects on Campylobacter. Development of a suitable alternative to thiosulfate as a reducing agent in the recovery medium may be required in to provide optimal conditions for recovery of Campylobacter.