Effect of Generally Recognized As Safe Compounds to Control the Growth of Aspergillus flavus and it's Aflatoxin Production in Maize (Zea mays L.)

Abstract

The inhibitory effects of four Generally Recognized As Safe (GRAS) compounds; namely, sodium bicarbonate, ammonium bicarbonate, calcium chloride, and citric acid in different concentrations were evaluated on conidial germination and mycelial growth of Aspergillus flavus, an aflatoxin producing fungi on maize (Zea mays L.). The most effective compound, sodium bicarbonate in 40 g l1 concentration was used for spraying maize kernels before or after inoculation with the pathogen and aflatoxin content was determined by High Performance Liquid Chromatography with fluorescence detection. Both sodium bicarbonate and ammonium bicarbonate either completely inhibited or significantly reduced the in vitro mycelial growth and spore germination of A. flavus. However, citric acid or calcium chloride did not show any inhibitory effect on the growth of the fungus. Maize kernels that were first inoculated and then treated with sodium bicarbonate contained 11.9 pg kg'1 while those that were first treated with sodium bicarbonate followed by inoculation of the fungus contained 2.6 pg k g 1 of aflatoxin. Non-treated control kernels had high amount of aflatoxin (18.9 pg kg'1) while sodium bicarbonate on naturally infected kernels controlled the aflatoxin production by 100% .