One of the most severe quality defects in hard and semi-hard cheese, the late blowing defect, is caused by endospore-forming bacteria of the genus Clostridium. To minimize financial losses and waste of resources due to cheese spoilage, raw milk with elevated clostridial spore counts should not be used for the production of certain cheese types. In this context, threshold values of clostridial spore concentrations that cause quality defects in cheese are still under debate. To improve our understanding about late blowing defects, further information on the correlation between clostridial spore concentrations in milk and cheese quality is indispensable. Thus, the aim of this study was to monitor the microbiological quality of milk used for Alpine cheese production regarding clostridial endospore levels to facilitate the establishment of threshold spore concentrations that guarantee the absence of quality defects in Austrian cheese. For this purpose, we monitored clostridial endospore levels in vat milk of 4 Alpine dairies throughout the summer grazing period in 2018. Surprisingly, we observed almost complete absence of butyric acid-producing clostridia in milk and no blowing defects in cheese. Hence, critical clostridial spore concentrations could not be verified. Moreover, the observed low spore levels reveal that the prohibition of silage feeding and good farming practices effectively minimize clostridial endospore counts in milk and ensure the manufacture of high-quality cheese even if technological possibilities are limited.

中文翻译：

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简短交流：高山奶牛场的牛奶中梭菌孢子计数。

硬干酪和半硬干酪中最严重的质量缺陷之一，即后期吹制缺陷，是由梭状芽胞杆菌属的形成内生孢子的细菌引起的。为了最大程度地减少由于奶酪变质引起的经济损失和资源浪费，不应使用梭菌计数较高的生乳来生产某些类型的奶酪。在这种情况下，引起奶酪质量缺陷的梭菌孢子浓度阈值仍在争论中。为了增进我们对后期吹气缺陷的理解，关于牛奶中梭菌孢子浓度与奶酪品质之间相关性的进一步信息是必不可少的。从而，这项研究的目的是就梭菌内生孢子水平监测用于高山奶酪生产的牛奶的微生物质量，以促进建立阈值孢子浓度，从而保证奥地利奶酪没有质量缺陷。为此，我们在2018年整个夏季放牧期间监测了4个高山奶牛的还原乳中梭菌内生孢子的水平。令人惊讶的是，我们观察到牛奶中几乎完全没有产丁酸的梭状芽胞杆菌，而奶酪中没有起泡缺陷。因此，不能验证关键的梭菌孢子浓度。此外，