engleski

Antimicrobial activity of olive oil polyphenols against selected pathogenic and saprophytic Listeria strains

To determine the antibacterial activity of the total polyphenols and pure phenolic compounds from Croatian Ascolana monocultivar extra virgin olive oil against several pathogenic and non-pathogenic Listeria isolates. Phenolic compounds were characterized by high performance liquid chromatography (HPLC). Antimicrobial activity of pure phenolics: hydroxytyrosol (HT), tyrosol (T), 4-hydroxyphenylacetic acid (4-HPA), caffeic acid (CA), gallic acid (GA) and 3, 4-dihydroxyphenylacetic acid (3, 4-DPHA) as well as total polyphenols extracted from olive oil was assessed using broth dilution and time-kill curve methods. HT was the most inhibitory of tested polyphenols. The relatively lower MIC values of total polyphenol extract suggest the synergistic antibacterial effect of olive oil polyphenols. There was no difference in MIC values against different clinical isolates of L. monocytogenes ; however, laboratry strain of L. monocytogenes EGD showed slightly greater susceptibility rates to the polyphenols when compared to clinical isolates of bacteria and non-pathogenic L. innocua. Pure phenolic compounds and polyphenol extract inhibited the growth of Listeria species. Thus, the high polyphenol Ascolana monocultivar virgin olive oil possess potent antilisterial activities. Results suggest the possibility that olive oil polyphenols, particularly HT, could be efficiently used for protection against footborne pathogens.

olive oil; polyphenols; Listeria monocytogenes; antimicrobial activity

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