Synergistic Potential of Essential Oils in Controlling Aspergillus flavus, Aspergillus parasiticus, and Aflatoxin B1 Contamination in Peanuts

Aspergillus flavus and Aspergillus parasiticus are major aflatoxin-producing fungi that threaten global food safety. This study evaluates two benzaldehyde-rich essential oils from cassia and bitter almond kernels as eco-friendly antifungal agents for reducing aflatoxin contamination. Their combination (S _Ca−A ) exhibited strong synergy (FICI = 0.50), lowering the minimum inhibitory concentrations of both oils by 25% compared with individual treatments. In vitro , S _Ca−A significantly inhibited mycelial growth and spore germination, achieving ~ 84–93% biomass reduction at 1 MIC and > 97% inhibition at 2 MIC, while spore germination decreased by 98–99%. S _Ca−A also suppressed aflatoxin B₁ production by 34–50% in A. flavus and 26–28% in A. parasiticus . Scanning electron microscopy revealed severe deformation of hyphae and spores, indicating disruption of cell development. Biochemical assays confirmed compromised membrane integrity, with substantial leakage of intracellular proteins and nucleic acids, a 14-fold increase in malondialdehyde, and > 90% reduction in ergosterol levels. ATPase and alkaline phosphatase activities were also markedly reduced. In VOC-based biocontrol assays, S _Ca−A fumigation (1.07 µL/mL) inhibited A. flavus infection by 99% and completely prevented A. parasiticus contamination in peanuts. These results highlight S _Ca−A as a promising biodegradable antifungal and anti-aflatoxigenic agent for peanut preservation and postharvest food safety applications.