The in vitro and in situ effect of selected essential oils in vapour phase against bread spoilage toxicogenic aspergilli

The major objective of this study was to determine the antifungal, anti-toxicogenic and anti-sporulation effect of selected essential oils in the control growth of Aspergillus spp. by contact vapour method in in vitro and in situ condition. In continue, the effect of the essential oils treatment on the sensory profile of the bread was evaluated. In this study, ten essential oils (EOs), namely: thyme, clove, laveder, cumin, oregano, cinnamon, basil, rosemary, sage and lemongrass were tested against four strains of Aspergillus [Aspergillus flavus (SLO-B-201), Aspergillus parasiticus (SLO-B-219), Aspergillus ochraceus (SLO-B-245) and Aspergillus westerdijkiae (SLO-B-249)] isolated from bread samples. The Aspergillus strains were tested for potential production of mycotoxins by thin layer chromatography (TLC). The chemical composition of all tested EOs was identified by GC-MS and by gas chromatography with flame ionization detector (GC-FID). The antifungal activity, the minimum inhibitory doses (MIDs), anti-toxicogenic and antisporulation effect of the selected EOs were investigated by gas diffusion method in both, in vitro and in situ analyses. The results indicated that the thyme, clove, oregano, cinnamon and lemongrass were highly effective against tested toxigenic Aspergillus species in vapour phase. A treated bread sample with EOs does not have negative effect on the sensory properties of the breads, with exception of oregano and lemongrass. In this context, application EOs in vapour phase seems to be an effective, sustainable and safe method and promising alternative to the use of chemical inhibitors for bread preservation.