SUPPRESSION OF AFLATOXINS PRODUCTION IN ARTIFICIALLY INFESTED MAIZE GRAINS WITH ASPERGILLUS FLAVUS DURING STORAGE CONDITIONS

Abstract

Maize is the one of important crops in Egypt. Aflatoxins (AFs) are the foremost cancer present compounds by Aspergillus flavus (A. flavus) and cause health risks to human and animals. This study aimed to suppression of aflatoxins production by A. flavus by using different concentrations of natural substances (carnation oil, lemongrass oil, propolis and beewax) and chemical substances (salicylic acid and potassium sorbate) on maize grains. The strains of A. flavus were isolated from local maize grains on Potato Dextrose Agar (PDA) and detect its ability of aflatoxins production on coconut agar media. Samples (100g) of sterilized maize grains were treated individually with different concentration of carnation oil, lemongrass oil, salicylic acid and potassium sorbate (0.25, 0.5, 1.0, 2.0, 4.0 and 6.0%) and at concentration 1% and 4% for propolis and beeswax each, then inoculated with A. flavus and stored for 30 days at 28±2˚C. AFs reduction was determined by using High Performance liquid Chromatography (HPLC). All the tested substances had active effect in inhibition of AFs production by A. flavus in stored maize grains. The production of Aflatoxin B1 and B2 (AFB1 and AFB2) was decreased to about 93% and 99% at concentration of 0.25% carnation oil. Lemongrass oil almost completely inhibited AFB1and AFB2 production (99.12% - 99.98% and 99.98% -99.99%, respectively) at concentration of 2% - 6%. Potassium sorbate and salicylic acid (0.25%- 6%) that were significantly effective controlling aflatoxins production on maize grains compared with control. While, the propolis and beewax found to be the most active to protect maize grains against fungi. Natural substances, carnation oil, lemongrass oil, beewax and propolis had higher active effect at low concentration on aflatoxin production more than salicylic acid and more safe for human used.