Spoilage and poisoning of food by fungi are a major problem for the food industry and consumers. Decay may increase post harvest losses up to 50% without fungicide treatment. However the use of synthetic fungicides is becoming more restrictive and thus alternative treatments need to be developed to reduce environmental risk and satisfy the demands of consumer groups. Essential oils (EOs) have been shown to be effective against a range of fungi but their use may lead to changes in organoleptic properties. However the use of EO vapours may address this issue whilst still reducing contamination. As an initial screen, the effect of a citrus EO based antimicrobial vapour was tested against Penicillium chlysogenum, Aspergillus niger and Alternaria alternata using the disc diffusion method. Mycelial growth of all three species was completely inhibited and spore germination was reduced. The effect of the citrus EO vapour on mycelial growth and spore germination of the three fungi in culture and on the growth of A. alternata on tomatoes and P. chrysogenum and A, niger on grain was also determined. When exposed in culture mycelial growth was reduced by 44%, 34% and 67% for P. chrysogenum, A. niger and A. alternata respectively and, although the citrus EO vapour was not an effective treatment to reduce spoilage of tomatoes by A. alternata, it reduced the growth of A. niger and P. chrysogenum by 50-60% on grain over 10 days, suggesting its possible use in reducing spoilage in grain by these two species, especially as this treatment has previously been shown not to affect the organoleptic properties of raw vegetables. (C) 2011 Elsevier Ltd. All rights reserved.
