Therapeutic and Protective Impact of Acetic Acid Vapours on Germination Percent and Associated Fungi of Economic Grains During Storage

Abstract

Impact of AA fumigation on mycelial growth and spore germination of common storage fungi, as well as their curative and protective effects in the control of storage diseases in some commercial grains, was examined. Five concentrations of acetic acid vapours (0.0, 2, 4, 6, and 8 μl/l) were applied against mycelial growth and spore germination of A. flavus, A.niger, and F. verticillioides. The results showed that all tried concentrations suppressed mycelial growth and spore germination of all fungi. AA totally suppressed the spore germination and linear growth was obtained with AA at 8μl/l. Wheat, maize, and barley grains were treated with AA vapours at 0.0,050, 0.100, 0.150, 0.200, 0.250, and 0.300 ml/l in air for 60 minutes to investigate their effect on natural infection of the examined grains. The results showed that all tested concentrations significantly reduced natural infection in all tested grains. Natural infection was completely suppressed by AA at 0.250 ml/L for wheat and maize, and 0.300 ml/L for barley grain. At 0.200 mL/L, AA reduced natural infection by 86.0, 91.0, and 66.0% in wheat, maize, and barley, respectively. To evaluate their protective activity against artificial infection with A. flavus after 30, 60, and 90 days of storage, grains were treated with acetic acid vapours at 0.00, 0.100, 0150, 0.200, 0250, and 0.300 ml/l for 60 minutes. The results indicated that concentrations inhibited the artificial infection with A. flavus for 90 days in all tested grains except for AA at 0100 ml/l in barley grains. A. flavus infection was completely suppressed by AA at 0.250 ml/L for wheat and maize and 0.300 ml/L for barley grains. At 0.200 ml/L, AA reduced infection by 59.0, 76.0, and 58.0% in wheat, maize, and
barley, respectively. Previous AA concentrations were evaluated for their effect on grain germination. Wheat and maize grains showed greater sensitivity to acetic acid vapours than barley grains. The germination of white and maize grains was entirely prevented at 0.200 ml/l. Meanwhile, barley grain showed greater tolerance to acetic acid vapours. It required 0.300 ml/l to completely prevent germination.