Controlling the Production of Fumonisin B1 by Fusarium verticillioides in Corn Using Emulsified Essential Oils

Fusarium verticillioides is a major plant pathogen associated with maize contamination, posing a significant risk to food safety due to its production of fumonisins, mycotoxins with known toxicological effects. In this study, an initial screening of the antifungal activity of essential oils from clove, cinnamon, garlic, marjoram, thyme, oregano, rosemary, pepper, ginger, and eucalyptus was conducted. Based on the results, oregano essential oil (OEO) and thyme essential oil (TEO) were selected for further testing. The antifungal activity of these oils, alone and in combination (OTEO), as well as their emulsified formulations, was evaluated against the growth of F. verticillioides and the production of fumonisin B1 (FB1), both in vitro, using different culture media, and in artificially contaminated corn. OEO exhibited the highest antifungal efficacy, with minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) of 1.3 and 2.7 mg/mL, respectively. Emulsification significantly increased antifungal activity, reducing MIC values to 0.15 mg/mL in all treatments. Ergosterol content decreased by 60% compared to the control, indicating the disruption of membrane integrity and interference with sterol biosynthesis. Additionally, OEO reduced FB1 production by up to 69% in the in vitro test. Corn assays confirmed the efficacy of the emulsions, with treated samples showing undetectable FB1 levels after 10 and 30 days, without adversely affecting seed germination.