Gioddu, also known as "Miciuratu", "Mezzoraddu" or "Latte ischidu" (literally meaning acidulous milk), is the sole variety of traditional Italian fermented milk. The aim of the present study was to elucidate the microbiota and the mycobiota occurring in artisan Gioddu sampled from three Sardinian producers by combining the results of viable counting on selective culture media and high-throughput sequencing. Physico-chemical parameters were also measured. The overall low pH values (3.80-4.22) recorded in the analyzed Gioddu samples attested the strong acidifying activity carried out by lactic acid bacteria during fermentation. Viable counts revealed the presence of presumptive lactococci, presumptive lactobacilli and non-Saccharomyces yeasts. A complex (kefir-like) microbiota of bacteria and yeasts was unveiled through sequencing. In more detail, Lactobacillus delbrueckii was found to dominate in Gioddu together with Streptococcus thermophilus, thus suggesting the establishment of a yogurt-like protocooperation. Unexpectedly, in all the three analyzed batches from two out of the three producers Lactobacillus kefiri was also detected, thus representing an absolute novelty, which suggests the presence of bioactive compounds (e.g. exopolysaccharides) similar to those characterizing milk kefir beverage. Mycobiota population, studied for the very first time in Gioddu, revealed a more complex composition, with Kluyveromyces marxianus, Galactomyces candidum and Geotrichum galactomyces constituting the core species. Further research is needed to disclose the eventual occurence in Gioddu of probiotic cultures and bioactive compounds (e.g. exopolysaccharides, angiotensin-converting enzyme inhibitory peptides and antimicrobial compounds) with potential health-benefits for the consumers.

中文翻译：

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Gioddu（一种意大利发酵乳）的微生物学特征。

Gioddu，也称为“ Miciuratu”，“ Mezzoraddu”或“ Latte ischidu”（字面意思是酸性牛奶），是意大利传统发酵乳的唯一变种。本研究的目的是通过结合在选择性培养基上的可行计数结果和高通量测序结果，阐明从三个撒丁岛生产商取样的工匠乔杜中出现的微生物菌群和真菌菌群。还测量了理化参数。分析的Gioddu样品中记录的总体低pH值（3.80-4.22）证明了发酵过程中乳酸菌具有很强的酸化活性。可行的计数表明存在推定的乳球菌，推定的乳杆菌和非酵母菌。通过测序揭示了复杂的细菌和酵母菌（类牛乳菌状）菌群。更详细地说，发现焦糖乳杆菌与嗜热链球菌一起在焦德都占主导地位，因此表明建立了类似酸奶的协议。出乎意料的是，在三个生产者中的两个生产者的所有三个分析批次中，也都检测到了克菲乳杆菌，因此代表了绝对的新颖性，这表明存在类似于牛乳发酵乳饮料特征的生物活性化合物（例如胞外多糖）。在Gioddu进行的首次研究发现，分枝杆菌种群的组成更为复杂，其中以马克斯克鲁维酵母，念珠菌和半乳杆菌为核心物种。