A study was performed to establish detection methods by viscometric and pulsed photostimulated huminescence (PPSL) methods for irradiated com powder. Viscosity was determined using a Brookfield DV-rotation viscometer at 30℃ and operated at 30, 60, 90, 120, 150, 180, and 210 rpm. All irradiated samples showed a decrease in viscosity with increasing stirring speeds (rpm) and irradiation doses. Treatments at 1-3 kGy significantly decreased the viscosity. The photon counts of iffadiated corn powder were measured by PPSL immediately after irradiation and exhibited an increase with increasing irradiation dose. The photon counts of irradiated com powder almost disappeared with lapse of time in room conditions, but detection of irradiation was still possible after one month at darkroom conditions. Consequently, these results suggest that the detection of irradiated com powder is possible ty both viscometric and PPSL methods.