[Influence of metal nanoparticles on some microorganisms and microflora of unpasteurized beer]

The influence of nanoparticles of gold, silver, dioxide of cerium and zirconium in low concentration (0.5-7.5 mg/l) on pure cultures of Escherichia coli IEM-1, Bacillus subtilis BT-2, Candida scottii KB-2, Saccharomyces cerevisiae OB-3, Aspergillus niger R-3, Fusarium culmorum T-7 and Penicillium chrysogenum F-7 has been investigated. Silver nanoparticles, which caused a decrease of the amount of S. cerevisiae OB-3 cells by 90% after one hour of exposition, and led to almost complete death of vegetative and spore cells of B. subtilis BT-2 after 1 and 24 h of exposition, respectively, proved to be the most effective antimicrobial preparation. The decrease by one-two orders of the amount of B. subtilis BT-2 and of S cerevisiae OB-3 cells under the influence of preparations of silver nanoparicles in the presence of gold has been established. After adding silver preparations to the unpasteurized beer one could observe a decrease by 10-20% of bacterial and by about 40% of fungi which contaminated microflora on the 20th day of shelf-life. The paper is presented in Ukrainian.