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Rushan is a traditional dairy product consumed by the Bai people in the Yunnan Province of China, and its production still follows the traditional procedure of backslopping. However, how the microbial composition of raw materials and processing shape the microorganisms in rushan have not been systemically reported. In this study, high-throughput sequencing technique was applied to analyze the microbial compositions of raw milk, fresh rushan, curd whey, acid whey, and dry rushan at the phylum, family, genus, and Lactobacillus species levels. The results indicated that Lactobacillus , Lactococcus , and Streptococcus were dominant genera in rushan, whereas Lactobacillus kefiranofaciens and Lactobacillus helveticus were the 2 abundant species at the Lactobacillus species level. The network analysis indicated that raw milk mainly contributed to the microbial diversity of rushan, whereas acid whey made a great contribution to shaping the relative abundance of microbes in rushan and dramatically increased acid-producing genera, such as Lactobacillus and Acetobacter. The variation in microbial composition led to an increase in the relative abundance of pathways related to energy supply, acid production, fatty acid accumulation, cysteine, methionine, and lysine accumulation. The volatile profile of rushan was rich in esters and acids, and the high relative abundance of Lactobacillus might be associated with reduction of amino acid metabolism, degradation of unpleasant flavored xylene, and accumulation of decanoic, dodecanoic, and tetradecanoic acids in the products. The accumulation of medium long-chain fatty acids might result from the relative abundance of FabF , FabZ , and FabI , particularly from Lactobacillus amylolyticus and Lacticaseibacillus paracasei. [Display omitted] [ABSTRACT FROM AUTHOR]

Previous research reported that fermented yak milk had a diverse microbial composition. For this study, raw yak milk, qula, and fermented yak milk samples were collected from the Aba Tibetan autonomous region of China. The genus and species microbial composition of these samples were analyzed by high-throughput sequencing of 16S rRNA and groEL gene amplicons, and the volatile profile of the samples was quantified by gas chromatography–mass spectrometry. The results indicated variation in abundance of microbiota at the genus level among the fermented yak milk samples, with Lactobacillus as the most abundant genus in the majority of samples, ranging from 41.6 to 98.3%. The volatile profile of the samples varied among those collected from different villages. Correlations between bacterial composition and volatile compounds of the samples were also observed. Lactobacillus displayed a significant correlation with volatile compounds such as benzaldehyde, 2,3-pentanedione, ethanol, and ethyl acetate, whereas the samples with relatively high abundance of Streptococcus and Lactococcus displayed relatively low contents of volatile compounds. [ABSTRACT FROM AUTHOR]

China has a long history of producing and consuming fermented dairy products, and these traditional fermented dairy products (TFDP) have made important contributions to social development and human health. A detailed review of their characteristics is crucial to understand the functions of the various microorganisms that shape and define TFDP and the microorganisms' correlations with nutritional value, flavour and texture profile, and health benefits. This review focuses on the basic composition, microbial diversity, flavour profile, and health benefits of Chinese TFDP, and discusses the latest advancements in the understanding of their microbial ecology and flavour profiles. This review also examines the limitations of existing studies on the health benefits of these foods, to encourage the establishment of population-based diet and health databases, as well as randomised controlled trials addressing the mechanisms of health outcomes associated with the consumption of Chinese TFDP. [ABSTRACT FROM AUTHOR]