Lake Vostok is the deepest lake of Antarctica but has poor accessibility for study due to a thick glacial cover, however, water samples of this lake have become available for study just recently. Previously, only the microbiome of the ice cover samples was characterized. Here we report results of bacteriological seeding with subsequent identification of the heterotrophic microorganisms (bacteria and micellar fungi) present by 16S rDNA sequencing as well as results of a direct molecular study of the water microbiome. Surprisingly, the data obtained gave evidence of a predominant occurrence of common chemoorganotrophs that were rather psychrotolerant than psychrophilic. We isolated and described strains belonging to eight heterotrophic microbial species able to grow in a rich medium: six bacterial strains belonging to the species Microbacterium testaceum and Microbacterium trichothecenolyticum, Brevundimonas diminuta, Sphingomonas oligophenolica, Sphingomonas sp. and Sphingobium limneticum; and two fungal strains belonging to Dendryphion sp. and Cladosporium fusiforme. Direct study of 16S rDNA purified water samples confirmed the predominance of the Brevundimonas, Microbacterium, Bradyrhizobium, and Bacillus (Bacillus cereus) genera.

Protection of milk and dairy products from the effects of microorganisms and surface spoilage by the introduction of antimicrobial additives into packaging materials is a relevant and promising method. This publication is devoted to the preparation of a microparticle-modified ECOS preparation (silver salts and oxide) of a polyethylene package, the study of its properties and effects on the composition of milk. The basic physicochemical and microbiological parameters of milk during storage, as well as the possible migration of microparticles into milk and model liquids were studied by the methods of elemental analysis, scanning electron microscopy, and laser dynamic light scattering. It was found that such indicators as the content of fat, protein, lactose, dry substances remain unchanged within the experimental error for the initial milk, milk aged for 24 h in a glass container, and in contact with the modified polyethylene. When stored in glassware at room temperature (24 degrees C), the number of mesophilic aerobic and facultative anaerobic microorganisms in a day amounted to 8.1 . 10(6) CFU/cm(3), while the number of bacteria in the package with ECOS was 6 times less. It was found that the silver content in milk in contact with the modified polyethylene is negligible. The amount of zinc increases within 24 h by 10%, which is not critical in terms of milk quality indicators. It is shown that storing milk in a polymer package made with ECOS preservatives allows to suppress the development of microorganisms in cow milk, does not lead to any significant change in its composition and does not affect the quality.