Fungicidal effect of gaseous ozone in malting barley: Implications for Fusarium infections and grain germination

Abstract

Fungal infections pose a challenge in cereal grains, with Fusarium species, especially in malting barley, causing substantial economic losses and quality degradation. We investigated the effect of gaseous ozone on fungal deactivation and grain germination in spring malting barley, with focus on Fusarium spp. Five studies were performed: (1) ozone concentration (10–100 ppm) and exposure time (1–24 h) on high-moisture barley (19.8%); (2) ozone-treated barley stability over 120 days at 4 °C; (3) grain moisture content (12–20%); (4) relative humidity (23%, 54%, and 98%); and (5) temperature (13 °C, 20 °C, and 33 °C). Significant reductions in total fungal count and Fusarium spp. across all treatments were observed. Higher ozone concentrations and longer exposure times yielded greater reductions, with 100 ppm for 24 h achieving 99.2% and 98.2% reductions in total fungal count and Fusarium incidence, respectively. Grain germination exhibited a negative dose-dependent response but remained within recommended values. Ozone-treated barley preserved quality for 60 days in storage. Grain moisture content, relative humidity, and temperature did not significantly affect ozone's efficacy on fungi and grain germination. This study demonstrates ozone's efficacy against fungi while preserving barley germination, suggesting it as an eco-friendly fungicidal alternative.