Bacterial diversity in goat milk from the Guanzhong area of China

In this study, the V3 and V4 regions of the 16S rRNA gene from metagenomic DNA were sequenced to identify differences in microbial diversity in raw milk of Saanen and Guanzhong goats from the Guanzhong area of China. The results showed that Proteobacteria was the predominant phylum, accounting for 71.31% of all phyla identified in milk from the 2 breeds, and Enterobacter was the predominant genus (24.69%) within the microbial community. Microbial alpha diversity from Saanen goat milk was significantly higher than that of Guanzhong goat milk based on bioinformatic analysis of indices of Chao1, Shannon, Simpson, observed species, and the abundance-based coverage estimator. Functional genes and their likely metabolic pathways were predicted, which demonstrated that the functional genes present in the bacteria in goat milk were enriched in pathways for amino acid metabolism and carbohydrate metabolism, which represented 11.93 and 11.23% of functional genes, respectively. Physicochemical properties such as pH, protein, fat, and AA levels were also determined and correlations made with microbial diversity. We detected a significant difference in the content of lactose and 6 AA, which were higher in Saanen milk than in Guanzhong milk, and positively correlated with microbial carbohydrate metabolism and AA metabolism. Lactococcus, Lactobacillus, Bifidobacterium, Enterococcus, and Streptococcus, which are lactose-utilizing genera, were more abundant in Saanen milk than in Guanzhong milk. Higher levels of lactose in Saanen goat milk may explain its greater microbial diversity. We also demonstrated that most of the AA metabolism-related bacterial genera (e.g., Massilia, Bacteroides, Lysobacter) were enriched in Saanen goat milk. In this research, both probiotic and pathogenic bacteria were identified in goat milk, which provided the microbial information necessary to direct the utilization of beneficial microbial resources and prevent the development of harmful organisms in goat milk.     

Biodiversity of antifungal lactic acid bacteria isolated from raw milk samples from cow, ewe and goat over one-year period

Antifungal lactic acid bacteria (ALAB) biodiversity was evaluated in raw milk from ewe, cow and goat over one year period. Lactic acid bacteria were enumerated using 8 semi-selective media, and systematically screened for their antifungal activity against 4 spoilage fungi commonly encountered in dairy products. Depending on the selective medium, between 0.05% (Elliker agar) and 5.5% (LAMVAB agar) screened colonies showed an antifungal activity. The great majority of these active colonies originated from cow (49%) and goat (43%) milks, whereas only 8% were isolated from ewe milk. Penicillium expansum was the most frequently inhibited fungus with 48.5% of colonies active against P. expansum among the 1235 isolated, followed by Mucor plumbeus with 30.6% of active colonies, Kluyveromyces lactis with only 12.1% of active colonies and Pichia anomala with 8.7% of active colonies. In the tested conditions, 94% of the sequenced active colonies belonged to Lactobacillus. Among them, targeted fungal species differed according to the Lactobacillus group, whose presence largely depended on year period and milk origin. The Lb. casei and Lb. reuteri groups, predominantly recovered in summer/fall, were overrepresented in the population targeting M. plumbeus, whereas isolates from the Lb. plantarum group, predominantly recovered in spring, were overrepresented in the population targeting K. lactis, the ones belonging to the Lb. buchneri group, predominantly recovered in spring, were overrepresented in the population targeting P. anomala. Raw milk, especially cow and goat milks from the summer/fall period appeared to be a productive reservoir for antifungal lactobacilli.     

IDENTIFICATION OF MILK FROM GOAT, EWE AND COW IN THEIR MIXTURES BY POLYACRYLAMIDE GEL ELECTROPHORESIS

A rapid identification of milk from goat, ewe and cow was done in the raw milk mixtures by polyacrylamide gel electrophoresis method. Two kinds of milk were mixed in the following proportions: 75:25%, 50:50%, 25:75% (V/V). Raw goat milk was adulterated with increasing proportions of cow milk or ewe milk, and ewe milk was adulterated with cow milk. Ewe milk in goat milk was detected by the electrophoretic resolution of the casein fraction whereas cow milk in goat and in ewe milk was identified by the presence of two fast-moving whey proteins.     

Prediction of fatty acid profiles in cow,ewe, and goat milk by mid-infrared spectrometry

Mid-infrared (MIR) spectrometry was used to estimate the fatty acid (FA) composition in cow, ewe, and goat milk. The objectives were to compare different statistical approaches with wavelength selection to predict the milk FA composition from MIR spectra, and to develop equations for FA in cow, goat, and ewe milk. In total, a set of 349 cow milk samples, 200 ewe milk samples, and 332 goat milk samples were both analyzed by MIR and by gas chromatography, the reference method. A broad FA variability was ensured by using milk from different breeds and feeding systems. The methods studied were partial least squares regression (PLS), first-derivative pretreatment + PLS, genetic algorithm + PLS, wavelets + PLS, least absolute shrinkage and selection operator method (LASSO), and elastic net. The best results were obtained with PLS, genetic algorithm + PLS and first derivative + PLS. The residual standard deviation and the coefficient of determination in external validation were used to characterize the equations and to retain the best for each FA in each species. In all cases, the predictions were of better quality for FA found at medium to high concentrations (i.e., for saturated FA and some monounsaturated FA with a coefficient of determination in external validation >0.90). The conversion of the FA expressed in grams per 100 mL of milk to grams per 100 g of FA was possible with a small loss of accuracy for some FA.     

FUNGAL BIOTA ISOLATED FROM SPANISH CHEESES

Fungal biota, with special reference to the genus Penicillium, was studied in 52 samples of commercial cheeses (10 fresh, 17 semiripened and 25 ripened) made from different types of milk (cow, ewe, goat and mixed) produced in southern Spain. In 41 of the total of cheeses analyzed (79%) molds were isolated. Penicillium was identified in 63% of the samples , Mucor spp. in 27% , Geotrichum candidum in 17% and Cladosporium herbarum in 10%; eleven other fungal genera were detected ranging from 2 to 4%. Thirty-five species of Penicillium were analyzed with the following distribution: 7 in fresh cheese, 16 in semiripened cheese and 30 in ripened cheese. The incidence of Penicillium spp. was also greater in the cheeses with a higher degree of ripeness, i.e. 20% in fresh cheese, 71% in the semiripened and 76% in the ripened cheese.     

Vitamin profiles of kefirs made from milks of different species

Kefirs were produced under laboratory conditions using 10 different kefir grain cultures from different households, and reconstituted cow, ewe, goat and mare milk as substrates. The base milks and corresponding kefirs were examined for their content of water-soluble vitamins and orotic acid. On average, enrichment of vitamin concentration of>20% was observed with thiamine (only ewe milk kefirs), pyridoxine (kefirs from all milk species except cow milk), and folic acid (kefirs from all milk species except mare milk). Orotic acid content was reduced during fermentation throughout.     

Microbiological quality of raw milk used for small-scale artisan cheese production in Vermont: Effect of farm characteristics and practices

This study 1) evaluated the overall milk quality and prevalence of 4 target pathogens (Listeria monocytogenes, Staphylococcus aureus, Salmonella spp., and Escherichia coli O157:H7) in raw milk used for small-scale artisan cheesemaking and 2) examined specific farm characteristics and practices and their effect on bacterial and somatic cell counts (SCC). Raw milk samples were collected weekly from 21 artisan cheese operations (6 organic) in the state of Vermont that manufactured raw-milk cheese from cow (12), goat (5), or sheep (4) milk during the summer of 2008. Individual samples were examined for standard plate counts (SPC), coliform counts (CC), and SCC. Samples were also screened for target pathogens both quantitatively and qualitatively by direct plating and PCR. Overall, 86% of samples had SPC <10,000 cfu/mL, with 42% <1,000 cfu/mL. Additionally, 68% of samples tested were within pasteurized milk standards for coliform bacteria under the United States’ Grade A Pasteurized Milk Ordinance at <10 cfu/mL. Log₁₀ SPC and CC did not differ significantly among species. Similarly, method of sample delivery (shipped or picked up), farm type (organic or conventional), and duration of milking (year-round or seasonal) did not have significant effects on farm aggregated mean log₁₀ SPC, CC, or SCC. Strong positive correlations were observed between herd size and mean log₁₀ SPC and between log₁₀ SPC and CC as well as SCC when data from all animal species were combined. Although SCC for cow milk were significantly lower than those for goat and sheep milk, 98, 71, and 92% of cow, sheep, and goat milk samples, respectively, were within the compliance limits of the United States’ Grade A Pasteurized Milk Ordinance for SCC. Fourteen of the 21 farms (67%) were positive for Staph. aureus, detected in 38% of samples at an average level of 20 cfu/mL. Neither L. monocytogenes, E. coli O157:H7, or Salmonella spp. were detected or recovered from any of the 101 samples tested. Our results indicate that the majority of raw milk produced for small-scale artisan cheesemaking was of high microbiological quality with no detectable target pathogens despite the repeat sampling of farms. These data will help to inform risk assessments that evaluate the microbiological safety of artisan and farmstead cheeses, particularly those manufactured from raw milk.     

Goat milk allergenicity as a function of αs₁-casein genetic polymorphism

Cow milk allergy is the most frequent allergy in the first years of life. Milk from other mammalian species has been suggested as a possible nutritional alternative to cow milk, but in several cases, the clinical studies showed a high risk of cross-reactivity with cow milk. In the goat species, α_S1-casein (α_S1-CN), coded by the CSN1S1 gene, is characterized by extensive qualitative and quantitative polymorphisms. Some alleles are associated with null (i.e., CSN1S1*0₁) or reduced (i.e., CSN1S1*F) expression of the specific protein. The aim of this work was to obtain new information on goat milk and to evaluate its suitability for allergic subjects, depending on the genetic variation at α_s1-CN. Individual milk samples from 25 goats with different CSN1S1 genotypes were analyzed by sodium dodecyl sulfate PAGE and immunoblotting, using monoclonal antibodies specific for bovine α-CN and sera from children allergic to cow milk. A lower reaction was observed to 2 goat milk samples characterized by the CSN1S1* 0₁0₁ and 0₁F genotypes. Moreover, a fresh food skin prick test, carried out on 6 allergic children, showed the lack of positive reaction to the 0₁0₁ milk sample and only one weak reactivity to the 0₁F sample. The risk of cross-reactivity between cow and goat milk proteins suggests the need for caution before using goat milk for infant formulas. However, we hypothesize that it can be used successfully in the preparation of modified formulas for selected groups of allergic patients. The importance of taking the individual goat CN genetic variation into account in further experimental studies is evident from the results of the present work.     

Characterization and identification of yeasts from fresh and spoiled ground beef

From 28 samples of fresh and 4 of spoiled ground beef, 197 yeast isolates were obtained. Following identification, 79 strains resulted representing five genera with the genus Candida accounting for 82% of the strains and 61% of the identified species. Other genera found were Rhodotorula, Torulopsis, Trichosporon, and Cryptoccus. With one exception, only Candida was recovered from spoiled beef. The findings indicate that the yeast flora of fresh ground beef is characterized almost exclusively by Candida. Although not definitive, it appears that C. lipolytica, the most frequently isolated species, and C. zeylanoides are more indigenous to ground beef than any of the other 21 species identified.     

Cow and camel milk-derived whey and casein protein hydrolysates demonstrated effective antifungal properties against selected Candida species

Bioactive peptides derived from milk proteins are widely known to possess antibacterial activities. Even though the antibacterial effects of milk-derived peptides are widely characterized, not much focus is given to their antifungal characterization. Therefore, in this study, we investigated the antifungal properties of camel and cow whey and casein hydrolysates against various species of pathogenic Candida. The hydrolysates were produced using 2 enzymes (alcalase and protease) at differing hydrolysis durations (2, 4, and 6 h) and tested for their antifungal properties. The results showed that intact cow whey and casein proteins did not display any anti-Candida albicans properties, whereas the alcalase-derived 2 h camel casein hydrolysate (CA-C-A2) displayed a higher percentage of inhibition against Candida albicans (93.69 ± 0.26%) followed by the cow casein hydrolysate generated by protease-6 h (Co-C-P6; 81.66 ± 0.99%), which were significantly higher than that of fluconazole, a conventional antifungal agent (76.92 ± 4.72%). Interestingly, when tested again Candida krusei, camel casein alcalase 2 and 4 h (CA-C-A2 and CA-C-A4), and cow whey alcalase-6 h (CO-W-A6) hydrolysates showed higher antifungal potency than fluconazole. However, for Candida parapsilosis only camel casein alcalase-4 h (Ca-C-A4) and cow casein protease-6 h (Co-C-P6) hydrolysates were able to inhibit the growth of C. parapsilosis by 19.31 ± 0.84% and 23.82 ± 4.14%, respectively, which was lower than that shown by fluconazole (29.86 ± 1.11%). Overall, hydrolysis of milk proteins from both cow and camel enhanced their antifungal properties. Camel milk protein hydrolysates were more potent in inhibiting pathogenic Candida species as compared with cow milk protein hydrolysates. This is the first study that highlights the antifungal properties of camel milk protein hydrolysates.     

Internal transcribed spacer (ITS) sequencing reveals considerable fungal diversity in dairy products

Fungi are important spoilage organisms in dairy products. However, little is known about the diversity of naturally occurring spoilage fungi in raw milk and processed dairy products, due at least in part to the fact that classical fungal identification methods require considerable expertise. To gain further insight into the fungal diversity in the dairy system, we isolated fungi from raw milk, raw and pasteurized milk cheese, and yogurt using the selective dichloran rose bengal chloramphenicol agar. In total, 361 fungal isolates were obtained and further characterized by DNA sequencing of the internal transcribed spacer (ITS) region and the nuclear ribosomal large subunit (LSU) rRNA gene if needed. We conducted BLAST (https://blast.ncbi.nlm.nih.gov/Blast.cgi) searches of the ITS region sequences against the UNITE Database (https://unite.ut.ee/analysis.php), and selected other databases if needed, which allowed identification to the species level of 183 isolates and to the genus level of 107 of the 346 isolates that were successfully ITS sequenced. The isolates characterized represented 3 phyla and 19 genera; the most common genera isolated were Penicillium (25% of isolates), Debaryomyces (18%), and Candida (9%). This study not only provides, by using modern molecular tools, a baseline understanding of the types of fungi in dairy products, but also confirms that ITS sequencing is a useful approach for identification of fungal organisms found in the dairy food chain.     

Enumeration of clostridia in goat milk using an optimized membrane filtration technique

A membrane filtration technique developed for counting butyric acid bacteria in cow milk was further developed for analysis of goat milk. Reduction of the sample volume, prolongation of incubation time after addition of proteolytic enzyme and detergent, and a novel step of ultrasonic treatment during incubation allowed filtration of goat milk even in the case of somatic cell counts (SCC) exceeding 10⁶/mL. However, filterability was impaired in milk from goats in late lactation. In total, spore counts were assessed in 329 farm bulk goat milk samples. Membrane filtration technique counts were lower than numbers revealed by the classic most probable number technique. Thus, method-specific thresholds for milk to evaluate the risk of late blowing have to be set. As expected, the spore counts of milk samples from suppliers not feeding silage were significantly lower than the spore counts of milk samples from suppliers using silage feeds. Not only were counts different, the clostridial spore population also varied significantly. By using 16S rRNA gene PCR and gene sequencing, 342 strains from 15 clostridial species were identified. The most common Clostridium species were Clostridium tyrobutyricum (40.4%), Clostridium sporogenes (38.3%), Clostridium bifermentans (7.6%), and Clostridium perfringens (5.3%). The 2 most frequently occurring species C. tyrobutyricum and C. sporogenes accounted for 84.7% of the isolates derived from samples of suppliers feeding silage (n = 288). In contrast, in samples from suppliers without silage feeding (n = 55), these species were detected in only 45.5% of the isolates.     

Comparative analyses of microbial community diversities of Tibetan kefir grains from three geographic regions

Tibetan kefir grains are the traditional starter for fermented milk products in Tibet, China. To gain a deeper understanding of their bacterial and fungal community diversities, we compared kefir grains from three different regions, Nyingchi, Lhasa and Yangbajing, using high‐throughput sequencing. The results of sequence analysis grouped the reads into four bacterial and four fungal phyla, comprising 34 bacterial and 139 fungal genera, and 44 bacterial and 195 fungal species. Firmicutes and Proteobacteria were two dominant bacterial phyla, and Lactobacillus and Acetobacter were the dominant bacterial genera. Basidiomycota and Ascomycota were the dominant fungal phyla. There was significant difference in the Basidiomycota and Ascomycota among three regions (P < 0.05). A significant difference in genera was observed in the percentage of Saccharomyces, Trichosporon, Aspergillus and Candida between the samples from Nyingchi, Lhasa and Yangbajing (P < 0.05). Based on principal component analysis (PCA), the Tibetan kefir grain samples from Nyingchi could be distinctly differentiated from the other two regions in term of fungal community, but no obvious difference existed in the bacterial population of samples from the three regions.     

Investigation of bacterial and fungal diversity in tarag using high-throughput sequencing

This is the first study on the bacterial and fungal community diversity in 17 tarag samples (naturally fermented dairy products) through a metagenomic approach involving high-throughput pyrosequencing. Our results revealed the presence of a total of 47 bacterial and 43 fungal genera in all tarag samples, in which Lactobacillus and Galactomyces were the predominant genera of bacteria and fungi, respectively. The number of some microbial genera, such as Lactococcus, Acetobacter, Saccharomyces, Trichosporon, and Kluyveromyces, among others, was found to vary between different samples. Altogether, our results showed that the microbial flora in different samples may be stratified by geographic region.     

Simultaneous detection of cow and buffalo species in milk from China, India, and Pakistan using multiplex real-time PCR

Asian countries are major producers of cow and buffalo milk. For quality and authenticity purposes, a multiplex real-time PCR assay was developed to specifically and simultaneously detect DNA from these 2 bovine species. Targeting the cytochrome b gene of mitochondrial DNA, common PCR primers amplified a 105-bp fragment, and 2 fluorescent probes specific to either cow or buffalo were designed for their identification. Specificity was successfully tested on 6 other species, including sheep and goat, and sensitivity reached 1% of cow DNA in buffalo DNA and vice versa. As an evaluation, the method was tested using 119 freeze-dried Asian milk samples from regional industrial milk facilities. Although these samples did not cover the entire Asian zone, the multiplex assay indicated that approximately 20% of the samples (mainly from India) showed high levels of cross-contamination of cow milk by buffalo milk, and vice versa. Fast, sensitive, and straightforward, this method is fit-for-purpose for the authenticity control of Asian milk.     

Genetic diversity of thermoduric spoilage microorganisms of milk from Brazilian dairy farms

When correctly pasteurized, packaged, and stored, milk with low total bacterial counts (TBC) has a longer shelf life. Therefore, microorganisms that resist heat treatments are especially important in the deterioration of pasteurized milk and in its shelf life. The aim of this work was to quantify the thermoduric microorganisms after the pasteurization of refrigerated raw milk samples with low TBC and to identify the diversity of these isolates with proteolytic or lipolytic potential by RFLP analysis. Twenty samples of raw milk were collected in bulk milk tanks shortly after milking in different Brazilian dairy farms and pasteurized. The mean thermoduric count was 3.2 (±4.7) × 10² cfu/mL (2.1% of the TBC). Of the 310 colonies obtained, 44.2% showed milk spoilage potential, 32.6% were proteolytic and lipolytic simultaneously, 31% were exclusively proteolytic, and 48 (36.4%) were only lipolytic. Regarding the diversity, 8 genera were observed (Bacillus, Brachybacterium, Enterococcus, Streptococcus, Micrococcus, Kocuria, Paenibacillus, and Macrococcus); there was a predominance of endospore-forming bacteria (50%), and Bacillus licheniformis was the most common (34.1%) species. Considering the RFLP types, it was observed that the possible clonal populations make up the microbiota of different milk samples, but the same milk samples contain microorganisms of a single species with different RFLP types. Thus, even in milk with a high microbiological quality, it is necessary to control the potential milk-deteriorating thermoduric microorganisms to avoid the risk of compromising the shelf life and technological potential of pasteurized milk.     

Composition of the teat canal and intramammary microbiota of dairy cows subjected to antimicrobial dry cow therapy and internal teat sealant

Antimicrobial dry cow therapy (DCT) is an important component of mastitis control programs aimed to eliminate existing intramammary infections and prevent the development of new ones during the dry period. However, to what extent the microbiota profiles of different niches of the udder change during the dry period and following administration of DCT remains poorly understood. Therefore, the main objective of the present study was to qualitatively evaluate dynamics of the microbiota of teat canal (TC) and mammary secretions (i.e., milk and colostrum) of healthy udder quarters subjected to DCT using a long-acting antimicrobial product, containing penicillin G and novobiocin, in combination with internal teat sealant. To this end, TC swabs (n = 58) and their corresponding milk (n = 29) and colostrum samples (n = 29) were collected at the time of drying off and immediately after calving from clinically healthy udder quarters of Holstein dairy cows from a commercial dairy farm. All samples were subjected to DNA extraction and high-throughput sequencing of the V1–V2 hypervariable regions of bacterial 16S rRNA genes. Overall, shifts were more pronounced within the microbiota of mammary secretions than the TC. In particular, microbiota of colostrum samples collected immediately after calving were less species-rich compared with the pre-DCT milk samples. Proportions of several bacterial genera belonging to the phylum Proteobacteria, including Pseudomonas, Stenotrophomonas, and unclassified Alcaligenaceae, were enriched within the microbiota of colostrum samples, whereas Firmicutes genera, including Butyrivibrio, unclassified Clostridiaceae, and unclassified Bacillales, were overrepresented in pre-DCT milk microbiota. Apart from shifts in the proportion of main bacterial genera and phyla, qualitative analysis revealed a high degree of commonality between pre-DCT and postpartum microbiota of both niches of the udder. Most importantly, a considerable number of bacterial genera and species commonly regarded as mastitis pathogens or opportunists (or both), including Staphylococcus spp., unclassified Enterobacteriaceae, and Corynebacterium spp., were shared between pre-DCT and postpartum microbiota of mammary secretions. Percentage of shared bacterial genera and species was even higher between pre-DCT and postpartum microbiota of TC samples, suggesting that the DCT approach of the present study had limited success in eliminating a considerable proportion of bacteria during the dry period.     

Molecular analysis of bacterial communities in raw cow milk and the impact of refrigeration on its structure and dynamics

The impact of refrigeration on raw cow milk bacterial communities in three farm bulk tanks and three dairy plant silo tanks was studied using two methods: DGGE and cloning. Both methods demonstrated that bacterial taxonomic diversity decreased during refrigeration. Gammaproteobacteria, especially Pseudomonadales, dominated the milk after refrigeration. Farm samples and dairy plant samples differed in their microbial community composition, the former showing prevalence of Gram-positive bacteria affiliated with the classes Bacilli, Clostridia and Actinobacteria, the latter showing prevalence of Gram-negative species belonging to the Gammaproteobacteria class. Actinobacteria prevalence in the farm milk samples immediately after collection stood at about 25% of the clones. A previous study had found that psychrotolerant Actinobacteria identified in raw cow milk demonstrated both lipolytic and proteolytic enzymatic activity. Thus, we conclude that although Pseudomonadales play an important role in milk spoilage after long periods of cold incubation, Actinobacteria occurrence may play an important role when assessing the quality of milk arriving at the dairy plant from different farms. As new cooling technologies reduce the initial bacterial counts of milk to very low levels, more sensitive and efficient methods to evaluate the bacterial quality of raw milk are required. The present findings are an important step towards achieving this goal.     

Diversity of lactic acid bacteria associated with traditional fermented dairy products in Mongolia

Spontaneous milk fermentation has a long history in Mongolia, and beneficial microorganisms have been handed down from one generation to the next for use in fermented dairy products. The objective of this study was to investigate the diversity of lactic acid bacteria (LAB) communities in fermented yak, mare, goat, and cow milk products by analyzing 189 samples collected from 13 different regions in Mongolia. The LAB counts in these samples varied from 3.41 to 9.03 log cfu/mL. Fermented yak and mare milks had almost identical mean numbers of LAB, which were significantly higher than those in fermented goat milk but slightly lower than those in fermented cow milk. In total, 668 isolates were obtained from these samples using de Man, Rogosa, and Sharpe agar and M17 agar. Each isolate was considered to be presumptive LAB based on gram-positive and catalase-negative properties, and was identified at the species level by 16S rRNA gene sequencing, multiplex PCR assay, and restriction fragment length polymorphism analysis. All isolates from Mongolian dairy products were accurately identified as Enterococcus faecalis (1 strain), Enterococcus durans (3 strains), Lactobacillus brevis (3 strains), Lactobacillus buchneri (2 strains), Lactobacillus casei (16 strains), Lactobacillus delbrueckii ssp. bulgaricus (142 strains), Lactobacillus diolivorans (17 strains), Lactobacillus fermentum (42 strains), Lactobacillus helveticus (183 strains), Lactobacillus kefiri (6 strains), Lactobacillus plantarum ssp. plantarum (7 strains), Lactococcus lactis ssp. lactis (7 strains), Leuconostoc lactis (22 strains), Leuconostoc mesenteroides (21 strains), Streptococcus thermophilus (195 strains), and Weissella cibaria (1 strain). The predominant LAB were Strep. thermophilus and Lb. helveticus, which were isolated from all sampling sites. The results demonstrate that traditional fermented dairy products from different regions of Mongolia have complex compositions of LAB species. Such diversity of LAB provides useful information for further studies of probiotic strain selection and starter culture design, with regard to the industrial production of traditional fermented milk.