IASMA Research and Innovation Centre, Fondazione Edmund Mach, Food Quality and Nutrition Area, Innovative Food Technologies, San Michele all'Adige (TN), Italy.
Food Microbiol. 2011 Feb;28(1):43-51. doi: 10.1016/j.fm.2010.08.003. Epub 2010 Aug 14.
The aim of this study was to study the psychrotrophic microbiota developing during milk creaming of Grana Trentino cheese-making. 138 isolates from raw whole milk, cream and skim milk samples were screened by Randomly amplified polymorphic DNA PCR biotyping and representative strains of each biotype were characterised by partial 16S rRNA gene sequencing and enzymatic activity. Pseudomonadaceae were commonly isolated in cream samples while Streptococcaceae and Enterobacteriaceae in milk samples. Moraxellaceae and Flavobacteriaceae were found in both cream and milk samples. More than 80% of psychrotrophic isolates could grow at 37°C. All Flavobacteriaceae and half of Pseudomonadaceae biotypes displayed proteolytic activity on milk agar even at low temperatures such as 10°C. All Streptococcaceae and some of Enterobacteriaceae displayed acidifying activity and almost all Acinetobacter spp. (Moraxellaceae) displayed lipolytic activity towards tributyrin. Even if psychrotrophic bacteria is not the dominant microbial group in raw milk, their total number increases during creaming and becomes one of the most present group together with Lactic Acid Bacteria. Their enzymatic activities may be key players in determining milk quality for cheese making.
本研究旨在研究格雷纳特伦蒂诺奶酪制作过程中奶油化过程中产生的嗜冷微生物菌群。从生全脂奶、奶油和脱脂奶样品中筛选了 138 株分离物，通过随机扩增多态性 DNA PCR 生物分型进行筛选，并用部分 16S rRNA 基因测序和酶活性对每种生物型的代表性菌株进行了表征。假单胞菌科通常在奶油样品中分离，而链球菌科和肠杆菌科则在奶样中分离。莫拉氏菌科和黄杆菌科在奶油和奶样中均有发现。超过 80%的嗜冷菌分离株能在 37°C 下生长。所有黄杆菌科和一半的假单胞菌科生物型在低温下（如 10°C）对牛奶琼脂显示出蛋白酶活性。所有链球菌科和部分肠杆菌科显示出酸化活性，几乎所有不动杆菌属（莫拉氏菌科）对三丁酸甘油酯显示出脂肪酶活性。即使嗜冷菌不是生奶中占优势的微生物群，但在奶油化过程中，它们的总数会增加，并与乳酸菌一起成为最常见的菌群之一。它们的酶活性可能是决定奶酪制作中牛奶质量的关键因素。
