Survival ofCampylobacter jejuni in di¡erentgasmixtures

Campylobacter jejuni in fresh chilled chicken meat is known to be a major risk factor for human gastrointestinal disease. In the present study, the survival under chilled conditions of different C. jejuni strains exposed to different gas mixtures usually used for gas packaging of food was examined. Bolton broth and fresh, skinless chicken fillets were inoculated with six and four strains, respectively, and exposed to the gas mixtures 70/30% O2/CO2, 70/30% N2/CO2, and 100% N2 (the latter only investigated in broth) at refrigeration temperature (4–5 1C). In broth culture, the strains survived significantly longer when exposed to 100% N2 and 70/30% N2/CO2 than in the oxygen-containing gas mixture, 70/30% O2/CO2 (Po 0.0001). For the two anaerobic gas mixtures, the reductions only reached 0.3–0.8 log10 CFU mL 1 within the same period. In the presence of oxygen, the numbers of C. jejuni were reduced by a minimum of 4.6 log10 CFU mL 1 over 21 days. When inoculated onto chicken fillets, the C. jejuni strains also died significantly faster in the oxygen-containing gas mixture, 70/30% O2/CO2 (Po 0.0001), reaching reductions of 2.0–2.6 log10 CFU g 1 after 8 days. In the gas mixture without oxygen (70/30% N2/CO2), no reductions were observed.