Evaluation of indigenous lactic acid bacteria of raw mare milk from pastoral areas in Xinjiang, China, for potential use in probiotic fermented dairy products

Genetic-Phenotype Analysis of Bifidobacterium bifidum and Its Glycoside Hydrolase Gene Distribution at Different Age Groups

Human gut microbiota interfere with host development and aging. Bifidobacterium is a microbial genus found in the human digestive tract that has probiotic activities such as improving constipation and enhancing immunity. The species and numbers present change with age, but there has been limited research on probiotic gut microbiota at specific ages. This study analyzed the distribution of 610 bifidobacteria in subjects in several age groups (0-17, 18-65, and 66-108 y) using 486 fecal samples and determined the distribution of glycoside hydrolases based on genetic analysis of strains representing 85% of the Bifidobacterium species abundance in each age group. 6'-Sialyllactose is a major component of acidic breast milk oligosaccharides, which can promote human neurogenesis and bifidobacteria growth. Using genotypic and phenotypic association analysis, we investigated the utilization of 6'-sialyllactose by six B. bifidum strains isolated from subjects 0-17 and 18-65 y. A comparative genomic analysis of the six B. bifidum strains revealed differences in genomic features across age groups. Finally, the safety of these strains was evaluated by antibiotic gene and drug resistance phenotype analysis. Our results reveal that the distribution of glycoside hydrolase genes in B. bifidum varies with age, thus affecting the phenotypic results. This provides important insights for the design and application of probiotic products for different ages.

Draft Genome Sequence of Enterococcus dispar CoE-457-22, Isolated from Traditionally Produced Montenegrin Dry Sausage

Enterococcus dispar was isolated for the first time from synovial fluid and stool cultures and described as a new species in 1991. Here, we report the genome of E. dispar CoE-457-22, which was obtained from traditionally produced Montenegrin dry sausage (sudzuk).

Microbiological Characterization of Greek Galotyri Cheese PDO Products Relative to Whether They Are Marketed Fresh or Ripened

Galotyri is the most popular traditional Greek PDO soft acid-curd cheese. This study compared the microbial numbers and types and characterized the lactic acid bacteria (LAB) biota of two artisan-type Galotyri PDO cheese varieties, one marketed fresh (Brand-K) and the other ripened (Brand-Z). Two retail batches of each cheese variety were analyzed, and a total of 102 LAB isolates were biochemically identified. LAB (7.2–9.3 log CFU/g) prevailed in all cheeses, followed by yeasts (5.8–6.8 log CFU/g). Typical starter strains of Streptococcus thermophilus and Lactobacillus delbrueckii were the most abundant species in all batches. However, the fresh Brand-K cheeses had 1–3 log units higher thermophilic starter LAB counts than the ripened Brand-Z cheeses, which contained a more diverse viable LAB biota comprising Lacticaseibacillus paracasei, Leuconostocmesenteroides, Lentilactobacillus (L. diolivorans, L. kefiri, L. hilgardii), Pediococcusinopinatus/parvulus, few spontaneous nonstarter thermophilic streptococci and lactobacilli, and Enterococcus faecium and E. faecalis at higher subdominant levels.Conversely, the fresh Brand-K cheeses were enriched in members of the Lactiplantibacillus plantarum group; other LAB species were sporadically isolated, including Lactococcus lactis. All retail cheeses were safe (pH 3.9–4.0). No Salmonella spp. or Listeria monocytogenes were detected in 25-g samples by culture enrichment; however, Listeria innocua and coagulase-positive staphylococci (850 CFU/g) survived in one ripened batch. Gram-negative bacteria were <100 CFU/g in all cheeses. In conclusion, ripening reduced the starter LAB viability but increased the nonstarter LAB species diversity in the present Galotyri PDO market cheeses.

Antigenicity and Safety Evaluation of Lactiplantibacillus plantarum 7-2 Screened to Reduce α-Casein Antigen

α-Casein (α-CN) is considered the main allergen in bovine milk. Lactic acid bacteria (LAB) fermentation can hydrolyze milk protein and therefore reduce the antigenicity. In this paper, a LAB reducing the antigenicity of casein, identified as LactiplantibacillusPlantarum 7-2 (L. plantarum 7-2), was primarily identified by screening for protein hydrolysis ability using a method involving the determination of released free amino acid with further selection for the ideal antigenicity-reducing capability by enzyme-linked immunosorbent assay (ELISA). In order to verify the capability of L. plantarum 7-2 in inhibiting antigenicity, the standard milk proteins α-LA, β-LG, α-CN, β-CN and κ-CN were cultured with L. plantarum 7-2 for 18 h; The results of SDS-PAGE show that all the bands corresponding to the full length tested proteins became unclear or completely disappeared indicating that these proteins were hydrolyzed by L. plantarum 7-2. Correspondingly, the antigenicities of α-CN and β-LG were significantly reduced. L. plantarum 7-2 demonstrated negative hemolysis and nitrate reductase capabilities and was sensitive to the commonly used antibiotics ampicillin clindamycin tetracycline chloramphenicol, and erythromycin, demonstrating that L. plantarum 7-2 could be used in dairy product fermentation to reduce the antigenicity of milk protein.

Genome Sequences of Lactococcus garvieae and Lactococcus petauri Strains Isolated from Traditional Montenegrin Brine Cheeses

Lactococcus garvieae and Lactococcus petauri cause lactococcosis in fish. Both species have also been isolated from various food products and are considered emerging zoonotic pathogens. Here, we report the genomes of L. garvieae INF126 and L. petauri INF110, obtained from traditional Montenegrin brine cheeses.