Author : Deandrae L. Smith and Griffiths G. Atungulu
Source : Cereal Chemistry. 95, 1 (Sep. 2017) 130-140
Abstract : Background and objectives The impacts of microwaves set at the 915 MHz frequency and power levels 5, 10, and 15 kW on inactivation of harmful microbes across rice beds of different thicknesses 5, 10, and 15 cm, during microwave (MW) heating for 4, 6, and 8 min, were examined. Findings Increasing MW‐specific energy from zero (control) to 900 kJ/kg‐grain resulted in statistically significant decreases in rice microbial loads. At the highest specific energy, the reduction in the aerobic bacterial and aflatoxigenic fungal loads of Aspergillus flavus was 4.56 and 2.93 log colony‐forming units, respectively; virtually no statistically significant disparity of the A. flavus mold count was observed across the entire rice bed of up to 15 cm thickness. Conclusions Depending on selected MW‐specific energy, treatment of rice with MW set at the 915 MHz frequency has potential to achieve significant reductions in the harmful, A. flavus mold that inhabit rice; this has potential to reduce risks of rice contamination with aflatoxin. Significance and novelty Simultaneous drying and decontamination of harmful microbes, such as A. flavus, as accorded by the treatments using MW set at 915 MHz frequency, could improve overall rice drying efficiency with the merits of securing rice quality and safety, thereby improving returns to producers and processors.

Subject : Microbial load reduction. One pass drying. Rough rice drying. Specificenergy.