Plant Based Biocontrol of Toxigenic Aspergillus flavus and Aflatoxin B1 Production in Stored Grains Using Essential Oils

Aspergillus flavus is a widespread fungal contaminant known for producing aflatoxins, toxic secondary metabolites that affect the food quality and pose significant health risks to both humans and animals. Current study evaluated the susceptibility of Aflatoxin B1 producing A. flavus to five essential oils: E. cardamomum, C. longa, F. asafetida, S. aromaticum, and E. globulus. In vitro antifungal activity was assessed using agar well diffusion and microbroth dilution methods. S. aromaticum exhibited the most potent antifungal effect, with the largest inhibition zones (31.00 ± 1.00 mm) and the lowest Minimum Inhibitory Concentration (0.65 ± 0.22 µL/mL) and no cytotoxicity observed up to 100 µL/mL. Based on these findings, S. aromaticum oil was selected for in-situ testing to examine its inhibitory effect on fungal growth and AFB1 production in stored wheat, maize, and rice grains. Both intact and broken grains were tested at seven moisture levels (10-70 %) and categorized into growth control, negative control, and essential oil (EO) treated groups. Fungal growth (Colony Forming Unit per g) and AFB1 levels via High Profile Liquid Chromatography were recorded over 60 days. Broken grains exhibited higher levels of contamination. AFB1 levels were recorded highest at 40 % moisture and lowest at 10 % moisture level. S. aromaticum EO effectively reduced fungal growth across all conditions, with treated samples showing similar results to the negative control group. These findings highlight the potential of S. aromaticum essential oil as a natural preservative for grain storage.