Essential oil components eugenol and carvacrol (ranging between 100 and 200 ppm for carvacrol and between 250 and 750 ppm for eugenol ) were tested for antifungal activity against foodborne pathogenic fungal species A. carbonarius A1102 and P. roqueforti PTFKK29 in vitro and in situ conditions. In vitro antifungal activity of eugenol and carvacrol was evaluated by macrobroth method, while watermelon Citrullus lanatus L. Sorento slices were used for antifungal assays in situ. Selected components, eugenol and carvacrol showed significant inhibitory effect against tested fungi (A. carbonarius A1102 and P.roqueforti PTFKK29) in YES broth, as well as in in situ conditions. The minimal inhibitory concentration (MIC) of eugenol against A. carbonarius A1102 determined by macrobroth method was 2000 ppm, while against P.roqueforti PTFKK29 determined MIC was 1000 ppm. Carvacrol inhibited growth of A. carbonarius A1102 at minimal concentration of 500 ppm, while against P.roqueforti PTFKK29, MIC was 250 ppm. The assays in real food system – watermelon slices for eugenol and carvacrol show that inhibitory effect against both selected fungal species was concentration dependent. Furthermore, our results showed that antifungal effect of carvacrol as well as eugenol applied on watermelon slices in all concentrations was a result of effective synergy between an active antifungal compound and lower incubation temperature (15°C) in inhibition of A. carbonarius A1102. The present study suggests that the use of eugenol and carvacrol is promising natural alternative to the use of food chemical preservatives, in order to improve safety and quality of fresh-cut and ready-to-eat fruits.
Key words: eugenol, carvacrol, Aspergillus carbonarius A1102, Penicillium roqueforti PTFKK29, watermelon, antifungal effect
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