Effect of lemon grass (Cymbopogon citratus (DC.) Stapf.) treatments on Aspergillus flavus (SGS-421) infestation and aflatoxin B1 content ofmaize grains

Studies were conducted to determine the effect of lemon grass (Cymbopogon citratus (DC.) Stapf.) treatments on A. flavus (SGS-421) infestation of maize grains and aflatoxin B1 (AFB1) content of the grains. The experimental design followed a 2×2×5 factorial combination and effect of three factors: form of leaf addition (whole and powdered), form of water suspension (cold and hot), and level of concentration of leaf (0, 8, 10, 12 and 14%, w/w) and water suspension (0, 8, 10, 12 and 14%, w/v); were evaluated by analysis of the maize grains at 5 day interval for 30 days. The growth of the aflatoxigenic fungus and the aflatoxin content of the maize grains were evaluated with palm kernel agar and by thin layer chromatography method respectively. Powdered leaves of lemon grass at 14% (w/w) concentration prevented the growth of the fungus and AFB1 formation in the grains by the 25th day of incubation. This was followed by the whole leaves which reduced the fungal growth to 12.17% and aflatoxin content to 42.62%. Both the cold (8.90%) and hot suspensions (4.15%) had no significant (p 0.05) effect on the fungal growth after 10 days of incubation. On the contrary, there were significant (p 0.05) reductions in the aflatoxin content of grains treated with cold (10.24%) and hot suspensions (10.25%) at lowest concentrations of 8%. The findings showed that A. flavus infestation and AFB1 formation in maize grains can be controlled by co-storing powdered leaves of lemon grass with aflatoxin infected maize.