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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Crop and Commodity Protection Research » Research » Publications at this Location » Publication #317080
Title: Evidence for synergistic activity of plant-derived volatile essential oils against fungal pathogens of food

Author
item HOSSAIN, F. - Institut National De La Recherche Scientifique (INRS)
item Follett, Peter
item SALMIERI, S - Institut National De La Recherche Scientifique (INRS)
item VU, K - Institut National De La Recherche Scientifique (INRS)
item HARICH, M - Institut National De La Recherche Scientifique (INRS)
item LACROIX, M - Institut National De La Recherche Scientifique (INRS)

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2015
Publication Date: 8/30/2015
Citation: Hossain, F., Follett, P.A., Salmieri, S., Vu, K., Harich, M., Lacroix, M. 2015. Evidence for synergistic activity of plant-derived volatile essential oils against fungal pathogens of food. Food Control. 45:156-162.

Interpretive Summary: The antifungal activities of eight essential oils (EOs), namely basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree and thyme were evaluated for their ability to inhibit growth of Aspergillus niger, Aspergillus flavus, Aspergillus paraciticus and Penicillium chrysogenum as assessed by determining the minimum inhibitory concentration (MIC). The interactions between different EO combinations were performed using the checkerboard technique. The highest antifungal activities were exhibited by oregano and thyme and showed lowest MIC values for all fungi tested. A combined formulation of oregano and thyme resulted in a synergistic effect, showing enhanced efficiency against A.flavus and A.parasiticus and P.chrysogenum. Mixtures of peppermint and tea tree produced synergism against A.niger. A modified Gompertz model with parameters including maximum growth, maximum specific growth, and lag time under the various EO treatment scenarios showed adequately described and predicted the growth of the tested fungi under the experimental conditions.

Technical Abstract: The antifungal activities of eight essential oils (EOs) namely basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree and thyme were evaluated for their ability to inhibit growth of Aspergillus niger, Aspergillus flavus, Aspergillus paraciticus and Penicillium chrysogenum. The antifungal activity of the EOs was assessed by determining the minimum inhibitory concentration (MIC) using 96-well microplate analysis. The interactions between different EO combinations were done by the checkerboard technique. The highest antifungal activity was exhibited by oregano and thyme which showed lower MIC values amongst all the tested fungi. The activity of the other EOs which was capable of inducing growth inhibition, could be appropriately ranked in a descending sequence of cinnamon, peppermint, tea tree and basil. Eucalyptus and mandarin showed the least efficiency as they could not inhibit any of the fungal growth at 10,000 ppm. The interaction between these two EOs also showed no interaction on the tested species. A combined formulation of oregano and thyme resulted in a synergistic effect, showing enhanced efficiency against A.flavus and A.parasiticus and P.chrysogenum. Mixtures of peppermint and tea tree produced synergistic effect against A.niger. Application of a modified Gompertz model considering fungal growth parameters like maximum mold growths, maximum specific growth rates and lags time periods, under the various EO treatment scenarios, showed that the model could adequately describe and predict the growth of the tested fungi under these conditions.