Effect of essential oils extracted from the peels of grape fruits Citrus paradise Macfadon on growth of Aspergillus flavus Link ex Friesand Aflatoxin B1 production

Abstract

The present work was aimed to study the effect of the essential oil extracted from the peels of grape fruits Citrus paradision on growth of the fungus Aspergillus flavus and production of Aflatoxin B1. Preliminary screening of 19 isolates of A. flavus showed the ability of only 10 isolates to produce AFB1. Essential oil treatment showed gradual reduction of fungal growth with the increasing concentration of the oil using different test methods. Treating the fungus with the vapour of the essential oil showed the highest inhibitory activity at percentage of inhibition on solid media reaching 90.24% when added at 0.75 ml, followed by the dilution method in liquid media which revealed higher inhibition 87.15% at concentration 1%., then the dilution method in solid medium in which the percentage inhibition reached 89.69% at concentration of 2% varying concentration of essential oil showed also reduction in fluorescence intensity of AFB1 spots produced by the efficient isolate of A. flavus on TLC plate at concentration 0.125% compared with standard AFB1. No spots revealed on TLC plate from the fungal extract treated with 0.5% essential oil.