Food Microbiology Unit, Clinic for Ruminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria.
Int J Food Microbiol. 2011 Mar 1;145 Suppl 1:S24-30. doi: 10.1016/j.ijfoodmicro.2010.08.025. Epub 2010 Sep 18.
Detailed information on the natural microbial community present in raw milk, especially on the non-cultivable part of the milk microbiota, is rather limited as research in the past mainly focused on the detection of bacterial pathogens or microorganisms responsible for the deterioration of raw milk. In frame of the EU project BIOtracer raw milk samples from three different European countries were analyzed to gain a deeper insight into the diversity of the natural bacterial flora of raw milk by combining culture-dependent and -independent methods. Fourier-transform infrared (FTIR) spectroscopy was used as rapid and cost efficient metabolic fingerprinting technique to monitor the cultivable microbiota of raw milk. In addition, direct sequencing was applied to acquire additional information on the non-cultivable part of the bacterial raw milk flora. Subsequent performed biostatistical analysis revealed a high correlation between the data gathered by culture-dependent and independent methods. Both methods revealed significant differences between the microbiota of farm and dairy tank milk, which appeared to be rather independent from geographical regions. Based on the results from FTIR and direct sequencing, the predominant bacterial raw milk flora was determined, representative isolates were selected and two model floras, representative for farm tank milk and dairy bulk tank milk, were compiled. These bacterial model floras for raw milk are now available for the Biotracer partners and can be used for validation purposes or contamination scenarios. The knowledge gained on the variation range of the normal raw milk microbiota will help to identify raw milk with divergent microbiota, pointing towards potential pathogen contaminations.
有关生牛乳中天然微生物群落的详细信息，特别是牛乳微生物群中非可培养部分的信息，相对有限，因为过去的研究主要集中于检测细菌病原体或导致生牛乳变质的微生物。在欧盟项目 BIOtracer 的框架内，分析了来自三个不同欧洲国家的生牛乳样品，通过结合培养依赖和独立的方法，深入了解生牛乳天然细菌菌群的多样性。傅里叶变换红外（FTIR）光谱被用作快速且具有成本效益的代谢指纹图谱技术，以监测生牛乳可培养微生物群。此外，直接测序被应用于获取生牛乳细菌菌群中非可培养部分的附加信息。随后进行的生物统计分析表明，培养依赖和独立方法收集的数据之间具有高度相关性。这两种方法都揭示了农场和奶罐生牛乳菌群之间的显著差异，这些差异似乎与地理位置相对独立。基于 FTIR 和直接测序的结果，确定了主要的生牛乳菌群，选择了代表性分离株，并编译了两个代表农场奶罐和乳制品罐中牛奶的细菌模型菌群。这些生牛乳细菌模型菌群现在可供 Biotracer 合作伙伴使用，可用于验证目的或污染情况。关于正常生牛乳微生物群变化范围的知识将有助于识别具有不同微生物群的生牛乳，从而表明可能存在病原体污染。
