ISOLATION, CHARACTERIZATION AND CONTROL OF MYCOTOXIGENIC FUNGI ON DETERIORATING PEARL MILLET (Pennisetum glaucum (L). R. Br) GRAINS

Abstract

In this study, the natural occurrence of fungal contamination of Pearl millet (Pennisetum glaucum) grains purchased at Oba market in Akure, Ondo State, Nigeria was evaluated. Eighty samples of Pearl millet grains were analyzed by direct plating method on Potato Dextrose Agar. A total of fourteen (14) fungi were isolated. The most frequently isolated fungal species were Aspergillus spp, Penicillium spp and Fusarium spp. The isolates were screened for the ability to produce mycotoxin. The antifungal efficacy of Lime (Citrus aurantifolia Linn (CA) peels and Ginger (Zingiberofficinale Roscoe) rootswere investigated against mycotoxigenic isolates using methanol, water and acetone as extraction solvents. Different concentrations: 0.1 g/ml, 0.2 g/ml, 0.3 g/ml, 0.4 g/ml and 0.5 g/ml of the extracts were assessed against mycotoxigenic isolates using the agar well diffusion technique and fifty milligrams per millilitre of fluconazole and griseofulvin were used as control in the experiment. The results indicated that Z. officinale demonstrated a wider spectrum of antifungal property (14.17 mm, 10.20 mm) on Aspergillus spp compared with C. aurantifolia(10.33 mm, 8.13 mm). No inhibition was observed using extracts of C. aurantifoliaon Penicillium spp isolated except P. oxalicum(13.17 mm). However, C. aurantifoliademostrateda wide spectrum of antifungal property on Fusarium spp (12.07 mm, 9.07 mm). Methanolic extracts of both plant materials displayed higher antimicrobial activities compared with aqueous and acetone extracts. No antifungal activity was observed against P. frequentans and Beauvaria bassiana using all the extracts of both plant materials. The results clearly revealed that the methanolic extracts of these plants could be used for the preservation of Pearl millet grains and by extension other cereal grains against fungal infections during storage.