The authors performed screening of a wide range of mycotoxins by ultra-high-performance liquid chromatography combined with tandem mass spectrometry (UHPLC-MS/MS) in various tea products distributed on the RF market. Samples were selected in retail outlets and obtained from wholesalers. Seventy-seven tea samples were examined: 54 out of them were Camellia sinensis tea, not packed (semi-finished product) and packed; 23 were mono-and multi-component herbal tea. The analytes were 29 mycotoxins including regulated in food products (aflatoxins, ochratoxin A, deoxynivalenol, fumonisins, T-2 toxin and zearalenone), their derivatives and structural analogues (A and B trichothecenes, structural analogues of zearalenone); emergent mycotoxins (sterigmatocystin, mycophenolic acid, moniliformin, enniatins, beauvericin and Alternaria toxins). C. sinensis tea samples, both green and black, were the least contaminated. In contrast, multi-component herbal tea samples tended to be simultaneously contaminated with several mycotoxins (over five) both regulated in food products and emergent ones. Beauvericin, mycophenolic acid and enniatin B were the most frequently detected. Toxigenic properties of mixed tea microflora were examined in vitro. Model experiments were carried out on a substrate consisting of C. sinensis green tea leaves in the absence of any growth factors. Mixed mycoflora from tea, which contained potentially toxigenic species of mold species proved to be capable to simultaneously produce substantial quantities of several mycotoxins including emergent ones. Mycotoxins accumulation amounted to 290 and 5,600 µg/kg of fumonisins B1 and B2 accordingly; 130 µg/kg of zearalenone; 14 µg/kg of sterigmatocystin; 160 µg/kg of alternariol methyl ester. The present survey indicates there is a potential health risk associated with mycotoxins in teas, especially herbal ones. The systematic study of contamination of tea products distributed in the RF with mycotoxins and their producers has been performed for the first time. Long-term monitoring over variety of mycotoxins in this kind of food products is essential for assessing its safety.

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.

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.

Федеральный исследовательский центр питания, биотехнологии и безопасности пищи, Россия, 109240, г. Москва, Устьинский проезд, 2/14 Исследована микробная контаминация 54 образцов чая (Camellia sp.), черного и зеленого, в том числе с добавками, и чайных напитков, включая травяные. Нефасованный чай (полуфабрикат) был представлен из регионов: Индии, Индонезии, Шри-Ланки, Вьетнама, Кении, Китая; фасованный -из розничной торговли РФ. В целом 83,3 % образцов нефасованного чая соответствовали микробиологическому нормативу по плесеням; 16,7 % несоответствующих содержали плесени на уровнях (1,3-8,2)10 3 КОЕ/г. Выявлены различия в количестве плесеней в образцах с разным фракционным составом чая (в среднем КОЕ/г): крупнолистовые -2,3 · 10 2 ; среднелистовые -7,4 · 10 2 , мелколистовые (включая чайную пыль) -1,7 · 10 3 . Все фасованные чаи (Camellia sp.), в том числе с добавками, соответствовали требованиям установленного норматива. Доминирующий вид плесеней в чае (Camellia sp.) -Aspergillus niger. В травяных чаях выявлены высокие уровни микробного загрязнения: 55 % образцов не соответствовали установленному нормативу и содержали более 10 4-6 КОЕ/г плесневых грибов. Кроме того, 72,2 % этих образцов содержали более 10 5-8 КОЕ/г бактерий. Из числа травяных чаев, соответствующих нормативу, в 62,5 % образцов обнаружено большое количество бактерий: 8 · 10 5 -2 · 10 8 КОЕ/г. В микофлоре травяных чаев обнаружены Aspergillus, Penicillium, Alternaria, Fusarium -продуценты опасных микотоксинов, в том числе эмерджентных, что потенциально обусловливает загрязнение микотоксинами травяных чаев. Эти данные будут использованы в дальнейшем при идентификации опасности, обусловленной микотоксигенными грибами в чае и чайных напитках, в том числе травяных, а также для актуализации норматива.Ключевые слова: чай, Camellia sp., травяной чай, плесневые грибы, продуценты микотоксинов, продуценты эмерджентных микотоксинов, микотоксины, микробная контаминация, бактерии.

No abstract