Thermophilic and mesophilic lactic acid bacteria (LAB), such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus helveticus, and Lactococcus lactis, play a crucial role in the technological and sensory quality of Mozzarella cheese. In this study, the safety (genes encoding virulence factors and antibiotic resistance) and acidifying activity of autochthonous S. thermophilus cultures were evaluated in order to choose the most suitable strain for industrial application. The safe and good acidifying culture was tested in two buffalo Mozzarella cheese batches: Mozzarella cheeses produced with autochthonous culture (SJRP107) and commercial culture (STM5). The cultivable LAB was evaluated by culture-dependent method (plate counting) and the quantification of S. thermophilus cultures (commercial and autochthonous) were evaluated by culture-independent method RealT-qPCR (real-time quantitative polymerase chain reaction). The texture, physicochemical and proteolytic properties of the Mozzarella cheeses were similar for both batches. The nonstarter LAB count was higher during manufacture than in the storage, and the RealT-qPCR indicated the presence of S. thermophilus culture until the end of storage. S. thermophilus SJRP107 presented high potential for safety application in the production of Mozzarella cheese. Furthermore, considering the culture characteristics and their relationship with product quality, further studies could be helpful to determine their effect on the sensory characteristics of the cheese.

中文翻译：

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水牛莫扎里拉干酪中嗜热链球菌培养物的安全性和技术应用。

嗜热和中温乳酸菌（LAB），例如嗜热链球菌，德氏乳杆菌亚种。保加利亚，瑞士乳杆菌和乳酸乳球菌在莫扎里拉奶酪的技术和感官品质中起着至关重要的作用。在这项研究中，评估了嗜热链球菌培养物的安全性（编码毒力因子和抗生素抗性的基因）和酸化活性，以选择最适合工业应用的菌株。在两个水牛莫扎里拉奶酪批次中测试了安全且良好的酸化培养物：采用本地培养（SJRP107）和商业培养（STM5）生产的莫扎里拉奶酪。通过培养依赖性方法（平板计数）和S的定量来评估可培养的LAB。通过与培养无关的方法RealT-qPCR（实时定量聚合酶链反应）评估嗜热菌培养（商业和本地）。莫扎里拉奶酪的质地，理化和蛋白水解特性在两个批次中都相似。在制造过程中，非入门级LAB计数要高于存储中的数量，并且RealT-qPCR表示直到存储结束之前都存在嗜热链球菌培养物。嗜热链球菌SJRP107在莫扎里拉奶酪生产中具有很高的安全应用潜力。此外，考虑到培养特性及其与产品质量的关系，进一步的研究可能有助于确定其对奶酪感官特性的影响。