Inhibitors of mycotoxigenic fungi in corn grains stored under different humidity levels and time periods

Abstract

Corn production is compromised by mycotoxigenic fungi such as Fusarium, Aspergillus, and Penicillium, which reduce yield and quality from field to commercialization, causing gastrointestinal and carcinogenic risks in humans and animals. The objective of this work was to evaluate the efficacy of four fungal inhibitors in corn grains stored under different humidity and time conditions. Larrea tridentata extract (10 mL L⁻¹), azadirachtin (20 mL L⁻¹), aluminum phosphide (3 mg L⁻¹), and organic acid mixture (ascorbic 1%, citric 0.25%, lactic 0.25%) were evaluated against Aspergillus flavus, Aspergillus fumigatus, and Fusarium verticillioides in grains stored at 12, 15, and 18% humidity for 120 days. A factorial design (three fungi × three humidities × five treatments) in a completely randomized arrangement was used. The inhibitors showed residual activity of less than ten days. In humid chamber, fungal incidence increased from 8–19% at ten days of incubation to over 96% at thirty days. After ninety days of storage, A. flavus showed the lowest incidence (9.5%) in grains with 12% humidity, while A. fumigatus and F. verticillioides reached 42.0% and 15.0%, respectively. Aflatoxins were detected only in grains with 18% humidity, reaching maximum concentrations of 6.5 mg kg⁻¹ (A. flavus) and 11.0 mg kg⁻¹ (A. fumigatus). The results underscore the need to maintain humidity below 12% and apply early fungal inhibitors to prevent mycotoxin production during corn storage.