Antifungal effect of essential oils on Aspergillus westerdijkiae, A. ochraceus, A. flavus and Penicillium nordicum

Abstract

Essential oils are well known antimicrobials that may be used as alternative to synthetic preservatives in foods. The objective of the study was to evaluate the efficacy of different essential oils and their components on fungal growth and mycotoxins production. Minimal inhibitory concentrations (MICs) of essential oils of oregano, thyme, mint, fennel, pine needles and pinecones, and carvacrol, thymol, menthol and anisaldehyde were determined with broth microdilution method for Aspergillus westerdijkiae, A. ochraceus, A. flavus and Penicillium nordicum. Thymol, carvacrol and oregano, thyme and menthol essential oils were most efficient antifungals with growth inhibition of all strains already at concentrations 1/4 or even 1/8 of MICs in solid and liquid medium. Among tested fungi only A. westerdijkiae produced ochratoxin A, although growth was inhibited when antifungals were added to tested media. The study provides useful information of the potential application of essential oils as very efficient fungal growth inhibitors, but also of the risk of mycotoxin accumulation irrespective to fungal growth inhibition.