Survival of Campylobacter jejuni on raw chicken legs packed in high-oxygen or high-carbon dioxide atmosphere after the decontamination with lactic acid/sodium lactate buffer

Abstract

Quantitative risk assessment studies performed elsewhere showed the importance of reducing counts of Campylobacter jejuni on chicken carcasses for decrease of incidence of human campylobacteriosis. The current study indicated that 1.8 log CFU/g reduction of inoculated C. jejuni (6 log CFU/g) can be achieved by decontamination with lactic acid buffered with sodium lacatate (LA/NaLA, 10% w/v, pH 3.0). Subsequent packaging under modified atmosphere of 80% O-2/20%N-2 resulted in additional reduction of approximately 1.2 log CFU/g. These results were confirmed in naturally contaminated samples (2-3 log CFU/g) resulting in immediate reduction of present C. jejuni under the limit of enumeration (1 log CFU/g). However, enrichment showed presence of C. jejuni in 10 g of sample. Under 80% CO2 LA/NaLA treated C. jejuni remained detectable per 10 g until day 7, after which no positive samples were found until the end of the two-weeks storage. Under 80% CO2 LA/NaLA treated C. jejuni remained fluctuating at 10 CFU/g until the end of two-weeks storage. Control cells were reduced by approx. 1.5 log CFU/g during storage under 80% O-2/20% N-2, whereas no reduction was observed under 80% CO2/20% N-2. The present study showed the potential of buffered lactic acid and high-O-2 MAP to reduce C. jejuni both on inoculated and naturally contaminated samples. The immediate effect of decontamination was further extended by additive, not synergistic, effect of 80% O-2, suggesting the practical value of the tested concept in combating C. jejuni on chicken carcasses.