Inhibitory activity of the onion essential oil on growth Cladosporium cladosporioides, Emericella nidulans, and Eurotium spp.

This study was aimed at investigating the antifungal potential of onion (Allium cepa L. cultivar Kupusinski jabucar) essential oil against Cladosporium cladosporioides, Emericella nidulans, and Eurotium spp. isolated from food. The antifungal determination of onion essential oil was performed using the agar plate method. Applied concentrations of the onion essential oil (3.5, 7.0, 14.0, and 28.0 μL/100 mL) caused the delay or absence of fungal growth with different inhibitory effects on deceleration in the growth rate. Onion essential oil at a concentration of 14.0 μL/100 mL demonstrated a fungicidal effect (MFC) on the growth of C. cladosporioides and Eurotium spp. and inhibitory effect (MIC) for E. nidulans, while at a concentration of 28.0 μL/100 mL showed MFC on the growth of E. nidulans. Microscopic investigations showed that the application of onion essential oil caused changes in micromorphology of the investigated fungi (hyphae and reproductive organs deformation). This study proved that the tested onion essential oil could potentially be used as a protective agent against food-borne fungi.