Inactivation of aflatoxin producing molds by selected and broadband infrared wavelength treatments, and the effects of the treatments on rice milling quality

Abstract

This study investigated the impacts of selected and broadband infrared (IR) wavelength treatments with tempering step on inactivation of aflatoxigenic molds and the treatments’ effects on head rice yield (HRY). Rough rice was treated with different IR intensities, product-to-emitter gaps, and heating durations. Afterward, the samples were tempered at 60°C for 4 hr. Selected IR wavelength treatment at intensities of 15.71 and 10.08 kW/m2 for 20 and 30 s resulted in complete aflatoxigenic mold inactivation; broadband IR wavelength treatment with intensity of 10.84 kW/m2 for 30 s resulted in 1.09 log (cfu/g) reduction in aflatoxigenic mold load. Selected IR wavelength treatment (15.71 kW/m2 for 30 s) resulted in 7 percentage points reduction in the mean HRY. Incorporating a tempering step into treatments at IR intensities of 15.71, 10.08, 7.27, and 4.13 kW/m2 resulted in a complete aflatoxigenic mold inactivation. Also, tempering increased the mean HRY of the treated samples. Practical applications After optimizing the IR parameters tested in this study, the selected IR equipment can be scaled up and commercialized. This novel technique can be used to effectively inactivate aflatoxigenic molds and prevent aflatoxin accumulation on rice, while preserving the milling quality of rice.