Montet M P, Jamet E, Ganet S, Dizin M, Miszczycha S, Dunière L, Thevenot D, Vernozy-Rozand C
Unité de Microbiologie Alimentaire et Prévisionnelle (UMAP), Département de Santé Publique Vétérinaire, Ecole Nationale Vétérinaire de Lyon, Université de Lyon, 69280 Marcy l'étoile, France.
Int J Microbiol. 2009;2009:653481. doi: 10.1155/2009/653481. Epub 2009 Feb 11.
Growth and survival of acid-resistant (AR) and non-acid-resistant (NAR) Shiga-toxin-producing Escherichia coli (STEC) strains were investigated during the manufacture and ripening of microfiltered milk Camembert cheeses. The induction of acid resistance of the STEC strains in cheeses was also studied. Six different mixtures of AR and/or NAR STEC strains were inoculated separately into microfiltered milk at a level of 10(3) CFU mL(-1). The STEC counts (AR and NAR) initially increased by 1 to 2 log(10) CFU g(-1) during cheese-making. Thereafter, the populations stabilized during salting/drying and then decreased during the early stages of ripening. Exposing the STEC strains in artificially inoculated cheeses to simulated gastric fluid (SGF - pH: 2.0) reduced the number of NAR strains to undetectable levels within 40 minutes, versus 120 minutes for the AR STEC strains. AR and NAR STEC were able to survive during the manufacture and ripening of Camembert cheese prepared from microfiltered milk with no evidence of induced acid tolerance in NAR STEC strains.
在微滤牛奶卡门培尔奶酪的制作和成熟过程中，对耐酸（AR）和不耐酸（NAR）的产志贺毒素大肠杆菌（STEC）菌株的生长和存活情况进行了研究。同时也研究了奶酪中STEC菌株耐酸性的诱导情况。将六种不同的AR和/或NAR STEC菌株混合物分别以10(3) CFU mL(-1)的水平接种到微滤牛奶中。在奶酪制作过程中，STEC计数（AR和NAR）最初增加了1至2 log(10) CFU g(-1)。此后，菌数在腌制/干燥过程中稳定下来，然后在成熟早期减少。将人工接种奶酪中的STEC菌株暴露于模拟胃液（SGF - pH：2.0）中，40分钟内不耐酸菌株数量降至检测不到的水平，而耐酸STEC菌株则为120分钟。AR和NAR STEC能够在由微滤牛奶制成的卡门培尔奶酪的制作和成熟过程中存活，且没有证据表明NAR STEC菌株诱导产生了耐酸性。
