We used culture-and molecular-biology-based methods to investigate microbial diversity in the traditional

Here, we used pyrosequencing to obtain a detailed analysis of the microbial diversities of traditional fermented dairy products of Mongolia. From 22 Airag (fermented mare’s milk), 5 Khoormog (fermented camel’s milk) and 26 Tarag (fermented milk of cows, goats and yaks) samples collected in the Mongolian provinces of Arhangai, Bulgan, Dundgobi, Tov, Uburhangai and Umnugobi, we obtained a total of 81 operational taxonomic units, which were assigned to 15 families, 21 genera and 41 species in 3 phyla. The genus Lactobacillus is a core bacterial component of Mongolian fermented milks, and Lactobacillus helveticus, Lactobacillus kefiranofaciens and Lactobacillus delbrueckii were the predominant species of lactic acid bacteria (LAB) in the Airag, Khoormog and Tarag samples, respectively. By using this pyrosequencing approach, we successfully detected most LAB species that have been isolated as well as seven LAB species that have not been found in our previous culture-based study. A subsequent analysis of the principal components of the samples revealed that L. delbrueckii, L. helveticus, L. kefiranofaciens and Streptococcus thermophilus were the main factors influencing the microbial diversity of these Mongolian traditional fermented dairy products and that this diversity correlated with the animal species from which the milk was sourced.

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We analyzed lactic acid bacteria (LAB) and yeast populations in samples of airag, undaa, and hoormog, which are varieties of traditional fermented milk produced in Mongolia. To effectively detect lactobacilli, lactococci/streptococci/enterococci, and leuconostocs for complete analysis of the complex LAB population in airag, we developed two new primer sets and examined these primer sets in three different combinations using denaturing gradient gel electrophoresis (DGGE). DGGE analysis revealed the diversity of the LAB and yeast populations in these traditional fermented milk samples; six to 11 LAB and yeast species were detected. The species common to all samples include Lactobacillus helveticus, Leuconostoc mesenteroides, Lactococcus lactis, and Kluyveromyces marxianus. Lc. raffinolactis, Enterococcus faecium/ hirae/durans/villorum/ratti, Streptococcus thermophilus, L. kefiranofaciens, L. kefiri/buchneri, Leu. citreum, and Leu. lactis were detected in multiple samples, while lactose non-fermenting Saccharomyces cerevisiae was only detected in one sample of hoormog.Keywords: traditional fermented milk, denaturing gradient gel electrophoresis, lactic acid bacteria, yeast *To whom correspondence should be addressed. E-mail: mari-miya@snowbrand.co.jp IntroductionAirag is the most popular traditional fermented milk in Mongolia. It is made using horse milk and has a low alcohol content (normally less than 3%). Similar types of traditional fermented milk are also consumed in Inner Mongolia (chigee and tsege) and Russia (koumiss). Hoormog and undaa, respectively prepared using the milk of camel and cow, are less popular types of Mongolian fermented milk.Airag is generally fermented by adding fresh raw milk to a small quantity of previously prepared airag, and the mixture is then stirred several thousand times. At the end of the horse lactation period, Mongolian people prepare hurunge, naturally dried airag which is stored for use as a starter culture in the following summer.