Enhanced insecticidal efficacy and grain quality through optimized ozone adsorption in stored grain

Ozone (O₃) fumigation is a promising fumigant as a safe and sustainable alternative for stored grain pest control, but its efficacy is hindered by grain adsorption, reducing ozone bioavailability. This study systematically investigated ozone adsorption in wheat, maize, and rice under varying conditions of grain temperature (15–35 °C), moisture content (12.5–16.5 %), and ozone concentration (200–500 ppm) using response surface methodology. Moisture content emerged as the predominant factor influencing ozone adsorption, followed by grain temperature and ozone concentration. The optimal conditions for minimizing ozone adsorption were 18.3 °C, 13.0 % moisture content and 471 ppm for wheat; 19.2 °C, 12.5 % moisture content and 486 ppm for maize; and 17.1 °C, 12.7 % moisture content and 436 ppm for rice. Optimized conditions significantly minimized ozone adsorption, enhancing insecticidal efficacy against Tribolium castaneum, reducing LT₅₀ and LT₉₉ values, particularly in rice, which showed high ozone adsorption. Furthermore, optimized ozone fumigation effectively decreased microbial contamination while preserving critical quality parameters, including germination percentage, nutritional integrity, and minimal lipid oxidation. This study highlighted the crucial role of adsorption control in ozone fumigation and provides a strategy for facilitating the more effective and widespread application of ozone fumigation in grain storage systems.