Plant essential oils as natural fungicides against stored product fungi

Stored product fungi cause severe degradation of food items during storage and also cause health hazards by secreting various mycotoxins. Due to negative concerns on health and environment, many synthetic fungicides have been removed through the Food Quality Protection Act in the United States which hinted the exploration of plant products as safe fungicides. Different in vitro studies have demonstrated antifungal activity of plant essential oils (EOs) against a wide range of food spoiling fungi. EOs are composed of a large number of components having several targets in the cell. Being hydrophobic in nature, they easily pass through plasma membrane, cause partition in the lipids of the cell membrane, and make it more permeable and subsequently leakage of cell contents occur. EOs also reported to retard biosynthesis of ergosterol, the fungal specific sterol, making EOs specific to fungal target. A few EO based fungicides viz. Sporan, Promax etc. are already commercially available and many are in process. Most of the EOs are in the list of generally recognized as safe (GRAS) in the U.S.A. favouring their use as safe fungicide. In the present chapter, the potential of plant EOs as safe fungicide for future application is discussed. In addition, mode of antifungal action, safety concerns and challenges for future prospects are also discussed.