Bacterial adhesion and further development of biofilms on food-related surfaces are concerning due to the increased resistance of microorganisms within the complex microbial community. Our study focused on adhesion of Campylobacter jejuni via monitoring culturability, activity of adhered cells and quantification of attached biomass. We have developed an effective method for the quantification of adhered bacterial cells in microtiter plate with real-time PCR. Absolute quantification for creating the standard curve was made with digital PCR. We have selected the most adhesive C. jejuni K49/4 chicken isolate. Further on we focused on evaluation of anti-adhesive effects of extracts from common juniper (Juniperus communis) as alternative strategy for prevention and control of bacterial cell adhesion. For this purpose, we prepared six extracts of common juniper: phenolic extract from berries, two phenolic fractions, isolated active compound amentoflavone, waste material extract after distillation (production of traditional drink “brinjevec”) and essential oil. Based on MIC values obtained for planktonic cells C. jejuni K49/4, we have selected subinhibitory concentration for extracts used to determine anti-adhesive effect. The adhesion of C. jejuni was reduced when treated with all juniper preparations. Phenolic extract and essential oil that showed the greatest anti-adhesive effect were used for further testing of adhesion under different growth conditions concerning: medium, surface roughness and mixed culture with L. monocytogenes. Juniper extracts expressed excellent anti-adhesion activity. Thus, the use of common juniper preparations can make an important contribution to the control of contamination with pathogenic campylobacters and thus to prevention of human infection.
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