Survival and growth of Campylobacter fetus subsp. jejuni on meat and in cooked foods

Abstract

Twelve strains of C. fetus ssp. jejuni isolated from humans and animals grew at temperatures ranging from 34-45.degree. C and pH minima between 5.7-5.9. Only 1 strain grew at pH 5.8 with lactic acid present at a concentration similar to that in meat. All strains had decimal reduction times of < 1 min at 60.degree. C. Further examination of a typical strain showed that it grew at 37.degree. C on high-pH meat but not at 37.degree. C on normal-pH meat. Bacterial numbers on both high (6.4)-pH and normal (5.8)-pH inoculated meat declined at a similar rate when the meat was stored at 25.degree. C. At -1.degree. C, the rate of die-off was somewhat slower on normal-pH meat but was very much slower on high-pH meat. The initial fall in bacterial numbers that occurred when meat was frozen was also greater for normal-pH meat than for high-pH meat. The organism exhibited a long lag phase (1-2 days) when grown in cooked-meat medium at 37.degree. C and died in meat pies stored at 37.degree. or 43.degree. C. Evaluation of the risk of Campylobacter contamination of red meat carcasses to human health must take into account the limited potential of the organism to grow or even survive on fresh meats and in warm prepared foods.