Effect of drying and ozonation process on naturally contaminated wheat seeds

Ozone application in postharvest grains has a potential reduction of insects, contaminating micro-organisms and a minimal or no effect on grain quality, in addition to being able to be used during the drying process. Thus, this study was evaluated the ozone exposure time applied with the drying air to wheat seeds at different temperatures, under levels of total fungal count, germination, vigor and electrical conductivity. The evaluations occurred shortly after the drying and ozonation process and in 45 days of storage. The achieved data showed that fungal reduction significantly improved with increased ozone exposure time and drying air temperature. The maximum reduction of fungal count was 92.86%, with reduction from 1.87 cfu/g to 0.13 cfu/g, when the wheat seeds was treated with ozone for 45 min and dried with air temperature at 50 °C. Results also showed that germination, vigor and electrical conductivity were not significantly affected by ozone exposure time and drying air temperature. Therefore, the gaseous ozonation applied at the initial instants of the drying process can be considered an effective and rapid way to reduce contamination by filamentous fungi in wheat seeds, not influencing their physiological quality. This method also showed efficacy after storage for 45 days.