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We analyzed microbe contamination of 54 tea samples (Camellia sp.), black and green one, including those with various additives, and tea infusions, including herbal ones. Tea that was not packed (semi-finished product) came from the following regions: India, Indonesia, Sri-Lanka, Vietnam, Kenya, China; packed tea was bought in retail outlets in the RF. Overall, 83.3 % samples of unpacked tea conformed to microbiological standards as per mold fungi; 16.7 % samples that didn't conform to them contained mold fungi in quantities equal to 1.3-8.2·10 3 CFU/g. We detected discrepancies in quantities of mold fungi in samples with different fraction structure of tea (in average CFU/g): large-leaved tea contained 2,3·10 2 CFU/g; middle-leaved, 7,4х10 2 ; small-leaved (including tea dust), 1,7·10 3 . All packed tea samples (Camellia sp.), including those with additives, conformed to the requirements fixed by the existing standards. Aspergillus niger mold fungi prevailed in examined tea (Camellia sp.). We revealed substantial microbe contamination in herbal teas; 55 % samples didn't conform to the existing standards and contained more than 10 4-6 CFU/g of mold fungi. Besides, 72.2 % of these samples contained more than 10 5-8 CFU/g of bacteria; 62.5 % samples of herbal teas that conformed to the standards were contaminated with great quantities of bacteria equal to 8·10 5 -2·10 8 CFU/g. We detected Aspergillus, Penicillium, Alternaria, Fusarium in herbal teas microflora; they were producers of hazardous mycotoxins, including emergent ones, and it could potentially cause contamination of herbal teas with mycotoxins. These data will be applied in future to identify hazards caused by mycotoxic fungi in tea and tea infusions as well as to update existing standards.

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Федеральный исследовательский центр питания, биотехнологии и безопасности пищи, г. Москва, Россия Токсигенные свойства микроскопических грибов Работа выполнена при поддержке Российского научного фонда (проект № 18-16-00077). Микроскопические грибы, инфицирующие растения в период вегетации, а также сельскохозяйственную продукцию при хранении, могут попадать в пищевые продукты и корма для животных и загрязнять их своими токсичными метаболитами-микотоксинами. Видовой состав и доля каждого из видов в комплексе выявляемых грибов могут меняться с изменением условий выращивания или хранения, что сопровождается изменениями в спектре микотоксинов. Наряду с известными и контролируемыми загрязнителями этого рода могут повышаться уровни содержания ранее не учитываемых токсичных грибных метаболитов, нуждающихся в дальнейшем изучении и оценке опасности их появления в продуктах питания. Обзор посвящен рассмотрению грибов из родов Fusarium, Aspergillus и Penicillium, представители которых могут продуцировать как уже регламентируемые в продуктах растениеводства микотоксины, так и прогнозируемые. В обзор включены также виды Alternaria spp., изучение которых выявило частую встречаемость и широкий спектр продуцируемых токсичных метаболитов, пока не нормируемых в пищевых продуктах.

We analyzed the formation of biofilms by 7 strains of Campylobacter genus bacteria and 18 strains of Enterobacteriaceae genus bacteria that were isolated from plant and animal raw materials, from finished products, and swabs from the equipment of the food industry. Biofilm formation on glass plates, slides and coverslips, microtubes made of polymeric materials and Petri dishes, and polystyrene plates of different profiles were analyzed. When studying the process of films formation, different effects on bacterial populations were simulated, including variation of growth factor composition of culture media, technique of creating of anaerobiosis, and biocide treatment (active chlorine solutions in a concentration of 100 mg/dm). The formation of biofilms by the studied cultures was assessed by the formation of extracellular matrix stained with aniline dyes on glass and polystyrene surfaces after incubation; 0.1% crystal violet solution was used as the dye. The presence and density of biomatrix were assessed by staining intensity of the surfaces of contact with broth cultures or by optical density of the stained inoculum on a spectrophotometer. Biofilms were formed by 57% Campylobacter strains and 44% Enterobacteriaceae strains. The intensity of the film formation depended on culturing conditions and protocols, species and genus of studied isolates, and largely on adhesion properties of abiotic surfaces. In 30% of Enterobacteriaceae strains, the biofilm formation capacity tended to increase under the influence of chlorine-containing biocide solutions. Thus, we developed and tested under laboratory conditions a plate version of in vitro chromogenic model for evaluation of biofilm formation capacity of C. jejuni strains and studied stress responses to negative environmental factors.