Radiant heat treatments for corn drying and decontamination

Freshly harvested corn at moisture content of 24% wet basis (w.b.) was intermittently dried with infrared (IR) at intensities 2.39, 3.78, and 5.55 kW/m2 for 30, 50, and 180 s to safe storage-moisture content of 13% (w.b). Microbial load reduction, energy use and corn sensory and pasting qualities were evaluated. Experiments were carried out at product-to-emitter gap size of 450 mm. Increasing IR intensity from 2.39 to 5.55 kW/m2 resulted in average microbial load reductions of 2.6 and 2.9 log CFU/g at 180 and 30 s of intermittent IR heating, respectively. IR treatments reduced corn paste viscosity and stress cracks (p   .05). Drying corn to storage-moisture content with IR intensities 2.39 and 5.55 kW/m2, required 7.5 and 15.0 MJ/kg of water removed, respectively. Accelerated, Scaled-up IR drying and decontamination was achieved without affecting the corn quality; optimized treatments could potentially improve throughput and energy efficiency. Practical applications Freshly harvested, high moisture content corn must be dried within short duration to about 12–14% (w. b.) to prevent mold growth and preserve the overall corn quality. This research presents the following practical applications: Scaled up infrared (IR) treatment of corn with efficacy to significantly reduce drying time (9 to 22 min depending on infrared intensity and intermittent IR drying duration to dry freshly harvested corn at moisture content 23–13% wet basis). Capability of using intermittent IR heating to combine corn drying and decontamination in a single step while maintaining the quality of finished product. Potential of IR heating to inactivate heat resistant, mycotoxin-producing mold spores that are liable to survive conventional drying methods.