Cereal Chem. 94(4):705-711Infrared (IR) heating of corn followed by tempering treatments has potential to decontaminate corn of microbes without adverse effects on the overall corn quality. However, it is vital to determine the optimal processing parameters that maximize throughput and microbial load reduction and minimize drying energy without affecting overall corn quality. This study investigated effects of IR heating and tempering treatments on mold load reduction, corn color change, and drying energy requirements. Freshly harvested corn samples with initial moisture contents (IMCs) of 20, 24, and 28% wet basis were dried with a laboratory-scale IR batch dryer in one and two drying passes. The dried samples were then tempered for 2, 4, and 6 h at 50, 70, and 90°C. Results showed that mold load reduction ranged from 1 to 3.8 log colony forming units per gram of corn (log CFU/g) for one-pass treatments and from 0.8 to 4.4 log CFU/g for two-pass treatments as tempering temperature and tempering duration increased. Compared with the control, treatments resulted in reduction of the corn color parameter (DE) (P < 0.05). Energy expended to dry the corn varied between 1.7 and 2.5 MJ/kg for one-pass treatments and between 4.1 and 6.1 MJ/kg for two-pass treatments. This work showed that IR heating of corn has the potential to significantly decontaminate microbes on corn. The IR process may help producers combat mycotoxin issues in corn that result from mold contamination. † Corresponding

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), but insignificantly impacted corn color (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.

This study investigated the effects of broadband and selected infrared (IR) wavelength treatments of rough rice on microbial inactivation. Rough rice was treated at different IR wavelengths and product‐to‐emitter distances (110, 275, and 440 mm) followed by tempering at 60°C for 4 hr. The total mold and aerobic plate counts (APC) on non‐treated and treated samples were determined. Significant total mold reductions of 1.14 and 3.11 log CFU/g were obtained after IR heating using broadband and selected wavelengths, respectively (p < .05). The most significant reduction of APC using selected IR wavelength was 1.09 log CFU/g; the broadband IR wavelength had no effect on the mean APC. The IR treatments followed by tempering step resulted in greater reductions of total mold counts and APC (4.03 and 3.50 log CFU/g) in comparison to IR treatments without tempering (3.11 and 1.09 log CFU/g). Overall, bacteria showed more resistance to IR treatments than molds.

Vegetable soybean (Edamame) blanching with hot water/steam is an energy- and water- intensive process that may also result in compromised product quality. The effectiveness of infrared (IR) heating to dry and simultaneously blanch Edamame was investigated at heating intensities of 11.06, 8.43 and 6.99 kW/m2. Temperature, weight, texture, and green intensity of heated samples for various durations were determined. In general, product weight decreased during IR heating. The largest weight reduction (9.5 %) was achieved after 100 s of heating at the highest IR heating intensity. Hardness was reduced alongside treatment duration, reaching the lowest values (11172.9–10847 N) at 100 or 120 s despite heating intensity. The highest green intensity was recorded (0.33) for treatments at 100 or 120 s. The new process combined drying and blanching into one step which potentially improves processing efficiency and product quality.