Browsing by Author "Levchuk, O."
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- Identification of microorganisms that may contribute to the safety and quality of traditional foods and beverages consumed in the Black Sea regionPublication . Boyko, N.; Levchuk, O.; Mudryk, M.; Kutchak, I.; Dolgikh, A.; Bati, V.; Jorjadze, M.; Karpenko, D.; Sapundzhieva, T.; Alexieva, I.; Hayran, O.; Kocaoglu, B.; Kroon, P.; Costa, H.S.The main aim of the EU-funded BaSeFood project is to invesitgate the healthy properties of traditional foods and beverages of plant origin. Quality and safety of foods are largely dependent of the level of microbial contamination. For this study the majority of plants, as ingredients, of prioritized foods and drinks was obtained and collected from Georgia, Bulgaria, Russia, Turkey and Ukraine. The microbial species (strains) potentially belong to three different categories: (A) beneficial; (B1) detrimental of environment, and (B2) dangerous to human origin (classical “foodborne” pathogens) among all the variety of microbial contaminants that were determined. All isolated microorganisms have been identified with semi-automatic biochemical and serological tests and MULDY techniques. Beneficial species isolated from fresh green parts of plants included mainly Streptococcus lactis (carrot); enterococci, Enterococcus faecalis/faecium (hot pepper) in Bulgarian samples; Actinomyces israeli (kale, Turkey); Bifidobacterium longum (parsley), and Lactobacillus acidophilus (elderly flowers) in Ukrainian samples. The dominating opportunistic pathogenic bacteria (the category B1) belong mainly to species of Klebsiella pneumoniae and oxytoca (rose petals), Enterobacter cloacae (carrot), Proteus vulgaris/mirabilis (sorrel, dill, parsley, Ukraine and Bulgaria), and Str. agalactiae (nettle, corn, Georgia, and Turkey). Isolation of some bacteria (for example Serratia odorifera biogroup 1 and Pantoea agglomerans ) are plant specific. Salmonella typhi were obtained from sorrel (Ukraine), Shigella flexneri ABC from kale, crop and green beans (Turkey), and Listeria monocytogenes from bread (Georgia). The amount of bacteria with potential beneficial properties is significantly increased when selected traditional fermented foods and drinks are assessed: L. fermentum, B. breve and L. acidophylus (in boza), B. dentinum (in fermented beans, Turkey), A. israeli, L. plantarum and casei (kvass, Russia). We have concluded that the amount of beneficial bacteria was significantly less compared with the main dominating group of potentially pathogenic bacteria and foodborne pathogens were rarely found.
- Traditional foods of Black Sea Region countries as potential sources of prebiotic compounds and probiotic microorganismsPublication . Boyko, N.; Petrov, V.; Batit, V.; Levchuk, O.; Joriadze, M.; Sapundzhieva, T.; Hayran, O.; Beteva, E.; Costea, C.; Kaprel'yants, L.; Danesi, F.; Kroon, P.; Finglas, P.; Costa, H.S.; D'Antuono, F.Introduction Recommendations for a healthy life-style require the consumption of well-balanced foods preferably rich in biologically-active compounds and fibre. The range of claimed healthy foods and functional products is enormous; but their role in health and wellbeing is still largely unclear and incompletely specified. One possible way to substantially improve human health through diet is for active dietary ingredients to modulate normal gut microbiota. Methods The influence of methanol extracts of plants (dill, kale, persimmon, sideritis, pomegranate, and nettle) on intestinal microbial coenoses has been evaluated by detection of quantitative changes of key gut microbes. BALB/c mice were fed orally with diluted extracts in concentrations of 50 mg/mouse daily. Major groups of intestinal microbiota were analysed dynamically on days 1, 3, 7, 14 and 24 by using of classical isolation and identification methods. Results In order to be included in the EuroFIR composition data base, national (Bulgarian, Georgian, Romanian, Russian, Turkish and Ukrainian) traditional foods were prioritised in the first stage of the BaSeFood project and indexed according to the LanguaL system. The nutritional content of their macro- and microelements, vitamins and folate were determined [1-4]. The presence in these prioritised dishes and beverages and their major plant components of beneficial and potentially-pathogenic microbes, and foodborne pathogens were investigated [5]. In parallel a study was conducted to determine whether plants ingredients from national traditional foods are able to stimulate the commensal microbes in vivo and to inhibit potentially pathogenic strains [6-7]. Using the mouse model it could be shown that extract of dill inhibits both Enterococcus strains – E. faecalis and E. faecium, Klebsiella pneumoniae and Lactobacillus spp. and stimulates Bifidobacterium bifidum. A similar effect on bifidobacteria was observed after oral administration of kale but in this case an effect on all the other tested representatives of gut microbiota was not detected or was statistically insignificant. On day 3 nettle extract caused an unspecific stimulation of all the tested gut microbiota representatives, but on days 14 and 24 all the indices were approximately equal to their initial levels (for E. coli and K. pneumoniae), but lactobacilli and bifidobacteria were each dramatically reduced. Persimmon was the only extract able to specifically stimulate lactobacilli, and extract of pomegranate acts similarly for bifidobacteria. Extract of sideritis effectively inhibited K. pneumoniae but also commensal E. coli, leading in parallel to a statistically significant increase of bifidobacteria and a not substantially increase of lactobacilli. Discussion Plant components of traditional foods and fermented products are rich sources of beneficial bacteria [8]; these bacteria are present in plant ingredients or fermented products and can be used as potential sources of new probiotic strains. Plants are able to specifically modulate gut microbiota in a manner that is similar to prebiotics – even according to their definition they should not be digested by mammalian host. Conclusion It has been demonstrated that major plant components of traditional Black Sea regional foods can modulate the gut microbiome.