Rudol M, Scherer S
Technische Universität München, Institut für Mikrobiologie, Freising, Germany.
Int J Food Microbiol. 2001 Jan 22;63(1-2):91-8. doi: 10.1016/s0168-1605(00)00413-x.
The incidence of Listeria and Listeria monocytogenes in European red smear cheese was determined in order to assess whether the lack of recent outbreaks of listeriosis associated with cheese is due to improved hygenic conditions in the dairies. Out of European red-smear cheese samples of various types, 15.8% contained organisms of the genus Listeria, 6.4% of the samples were contaminated with L. monocytogenes, 10.6% with L. innocua, and 1.2% with L. seeligeri. Six cheese samples contained two or more Listeria species, including at least one L. monocytogenes isolate. The incidences of L. monocytogenes in cheeses from various countries were: Italy 17.4%, Germany 9.2%, Austria 10%, and France 3.3%. Listeria were found most frequently in soft and semi-soft cheese. Eight samples contained more than 100 L. monocytogenes cfu/cm2 cheese surface, 2 samples had counts above 10(4) cfu/cm2 cheese surface. Surprisingly, a higher incidence of L. monocytogenes was observed in cheeses made from pasteurized milk (8.0%) than in cheeses manufactured from raw milk (4.8%). Phage-typing of isolated Listeria strains clearly confirmed that (i) contaminations within dairy plants were persistent over a period of several weeks to months and (ii) that cross-contamination within the dairy plant is and important factor. Comparison of our data with past surveys seems to indicate that contamination of red smear soft cheese with L. monocytogenes has not decreased sufficiently over the past 15 years. It is therefore strongly recommended that these products are monitored carefully by cheese-making companies.
测定了欧洲红皮涂抹奶酪中李斯特菌和单核细胞增生李斯特菌的发生率，以评估近期与奶酪相关的李斯特菌病暴发减少是否归因于乳制品厂卫生条件的改善。在各类欧洲红皮涂抹奶酪样本中，15.8%含有李斯特菌属微生物，6.4%的样本被单核细胞增生李斯特菌污染，10.6%被无害李斯特菌污染，1.2%被西利格李斯特菌污染。六个奶酪样本含有两种或更多种李斯特菌，包括至少一株单核细胞增生李斯特菌分离株。不同国家奶酪中单核细胞增生李斯特菌的发生率分别为：意大利17.4%，德国9.2%，奥地利10%，法国3.3%。李斯特菌在软质和半软质奶酪中最常见。八个样本的奶酪表面每平方厘米含有超过100个单核细胞增生李斯特菌菌落形成单位（cfu），两个样本的计数高于每平方厘米10⁴cfu。令人惊讶的是，与用生牛奶制成的奶酪（4.8%）相比，用巴氏杀菌牛奶制成的奶酪中单核细胞增生李斯特菌的发生率更高（8.0%）。对分离出的李斯特菌菌株进行噬菌体分型明确证实：（i）乳制品厂内的污染在数周至数月的时间内持续存在；（ii）乳制品厂内的交叉污染是一个重要因素。将我们的数据与过去的调查进行比较似乎表明，在过去15年里，红皮软质奶酪被单核细胞增生李斯特菌污染的情况并未充分减少。因此，强烈建议奶酪生产公司对这些产品进行仔细监测。
