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A decrease in therapeutic effect of some live lacto- and bifdobacteria-based drugs for veterinary use has been observed for the last 20 years that urges scientists to search for new microorganisms possessing probiotic properties. Many studies in this feld are focused onBacillus subtilisthat is widespread in the environment and non-pathogenic for animals and humans. Results of tests ofBacillus subtilisfor its biological properties and antagonistic activity aimed at optimization of methodical approaches for detection of strain with the highest antagonistic effect on some opportunistic microorganisms and their further use as probiotics are described. Cultural morphological and biochemical characteristics of the tested strains conformed to the species characteristics ofBacillus subtilis.Tested strains were nonpathogenic for white mice. Tests showed that spore biomass could be prepared both in liquid and on solid nutrient media. Methodically, spore biomass preparation in liquid nutrient medium is preferable. The tests showed that spores emerged from anabiosis non-uniformly and it depended on original seed spore storage period. Spore cultures stored less than one year emerged from anabiosis more quickly. It was found that the spores formed more readily when the cultures were aerated with oxygen as well as that lag-phase culture medium had a stimulating effect onBacillus subtilisspore germination.Bacillus subtilisstrains were found to have antagonistic effect onEscherichia coli, SalmonellaandStaphylococcus. Area of growth inhibition of the said bacteria was 15–20 mm. TestedBacillus subtilisstrains could be proposed for use as probiotics.

Upward trend in the number of human yersiniosis cases, caused by bacterium Yersinia enterocolitica, is globally observed nowadays. This microorganism is widely spread in the environment, able to persist for prolonged periods in animal products and propagate under low temperatures. Basic infection sources are meat and meat products. In order to isolate Yersinia enterocolitica from food and feed samples horizontal method for the detection pursuant to GOST ISO 10273-2013 was used. It was noted, that Yersinia enterocolitica isolation is associated with certain difficulties, because the sample contains only small quantities of the agent and only the use of special techniques allows removing the concurrent microflora. It was proposed to use cold enrich­ment (4 ± 1) °C of the test material before conventional technique is started. The technique was validated pursuant to GOST ISO 16140-2011. As a result, it was established that validated method for Yersinia enterocolitica bacteria detection in food products, performed at the Microbiology Laboratory, is specific. The method sensitivity is 10 CFU/cm3. Intralaboratory reproducibility and repeatability were confirmed by relevant tests. Additional culture step at (4 ± 1) °C allows complete inhibition of non-psychrophilic microorganisms’ growth.

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