ANTIFUNGAL ACTIVITIES OF BACILLUS SUBTILIS STRAINS AGAINST AFLATOXIGENIC FUNGI ISOLATED FROM GRAINS

The increasing threat of mycotoxin contamination in food and feed products, particularly due to aflatoxigenic fungi such as Aspergillus flavus and Aspergillus parasiticus, has raised concerns over food safety and public health. Chemical pesticides are being used to manage mycotoxigenic fungi in crops, but they raise concerns about environmental and human health impacts, prompting a shift in agriculture toward more sustainable practices and safer alternatives. This study explores the potential of Bacillus subtilis to produce antifungal substances which inhibit the growth of aflatoxigenic fungi isolated from pre- and post-stored grains. B. subtilis strains isolated from fermented African locust beans (‘Iru’) were tested for antifungal activity against aflatoxigenic Aspergillus species. Isolated fungi were evaluated for their ability to produce aflatoxin on palm kernel agar. The antifungal activities of B. subtilis strains were assessed using the agar well diffusion method, followed by a dual culture assay for 14 days. From the agar well diffusion assay, the B. subtilis isolates were effective on only 7 of the 15 aflatoxigenic fungal isolates. For the dual culture assay, Bacillus subtilis I11MR showed the highest and most consistent antifungal activity with an inhibition rate ranging from 65.38% to 82.81%. This research showed that Bacillus subtilis strains can reduce the growth of aflatoxigenic fungi and can be considered as biocontrol agents to reduce aflatoxigenic fungi.