Department of Food Science, University of Parma, Parma, Italy.
Food Microbiol. 2013 Dec;36(2):207-15. doi: 10.1016/j.fm.2013.05.009. Epub 2013 Jun 10.
The aim of this study was to explore diversity and dynamic of indigenous LAB strains associated with a long ripened hard cheese produced from raw milk and undefined natural starter such as PDO Grana Padano cheese. Samples of milk, curd, natural whey culture and cheeses (2nd, 6th, 9th and 13th months of ripening) were collected from 6 cheese factories in northern Italy. DNA was extracted from each sample and from 194 LAB isolates. tRNA(Ala)-23S rDNA-RFLP was applied to identify isolates. Strain diversity was assessed by (GTG)5 rep-PCR and RAPD(P1)-PCR. Finally, culture-independent LH-PCR (V1-V2 16S-rDNA), was considered to explore structure and dynamic of the microbiota. Grana Padano LAB were represented mainly by Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus and Pediococcus acidilactici, while the structure and dynamic of microbiota at different localities was specific. The strength of this work is to have focused the study on isolates coming from more than one cheese factories rather than a high number of isolates from one unique production. We provided a valuable insight into inter and intraspecies diversity of typical LAB strains during ripening of traditional PDO Grana Padano, contributing to the understanding of specific microbial ecosystem of this cheese.
本研究旨在探索与由生牛乳和未定义天然干酪培养物（如 PDO 奶酪）制成的长期成熟硬质奶酪相关的土著 LAB 菌株的多样性和动态。从意大利北部的 6 家奶酪工厂收集了牛奶、凝乳、天然乳清培养物和奶酪（成熟 2 个月、6 个月、9 个月和 13 个月）的样本。从每个样本和 194 个 LAB 分离株中提取 DNA。tRNA(Ala)-23S rDNA-RFLP 用于鉴定分离株。通过（GTG）5 重复 PCR 和 RAPD(P1)-PCR 评估菌株多样性。最后，考虑使用非培养 LH-PCR（V1-V2 16S-rDNA）来探索微生物群的结构和动态。Grana Padano LAB 主要由鼠李糖乳杆菌、干酪乳杆菌、副干酪乳杆菌、德氏乳杆菌、瑞士乳杆菌和乳酸片球菌组成，而不同地点的微生物群结构和动态是特定的。这项工作的优势在于，它不仅关注于从一个独特的生产过程中获得的大量分离株，而是聚焦于来自多个奶酪工厂的分离株。我们深入了解了传统 PDO Grana Padano 成熟过程中典型 LAB 菌株的种间和种内多样性，有助于理解这种奶酪的特定微生物生态系统。
