New infrared heat treatment approaches to dry and combat fungal contamination of shelled corn

Abstract

AbstractCommercial application of infrared (IR) heat has been hampered by a lack of readily available data adaptable to high‐throughput (HT) drying requirements in the grain processing industry. This study evaluated the effectiveness of a continuous flow IR heating system to simultaneously dry and decontaminate corn over various drying bed thicknesses (1.5, 2.7, and 4.5 cm). Additionally, impacts of intermediate tempering treatment and variation of IR emitter angle (zero [E‐0] and 30 [E‐30] degrees) on drying and decontamination of the corn were determined. Although IR heating was able to dry and decontaminate corn at the initial moisture content (MC) of ≈21% wet basis (w.b.), moisture removal was most effective at the least bed thickness (1.5 cm). At 1.5 cm bed thickness, a safe storage MC (<14%) was achieved after 15 min of IR heating. At all the bed thicknesses, IR heating with intermediate tempering resulted in higher fungal inactivation than IR heating without tempering. Infrared heating of corn at 1.5 cm bed thickness plus tempering resulted in a total fungal count (TFC) reduction of 3.1 and 4.6 log CFU/g using IR emitters at E‐30 and E‐0° angles, respectively. However, increasing the bed thickness to 2.7 cm resulted in a TFC reduction of 4.8 and 4.6 log CFU/g using E‐30 and E‐0, respectively. Infrared heating using E‐0, compared to using E‐30, accelerated TFC reduction when corn samples were dried at 1.5 cm bed thickness. These results could help guide the design of HT corn drying and decontamination systems.