PULSED UV IRRADIATION USING DEEP UV-LED FOR INACTIVATION OF ESCHERICHIA COLI

Abstract

 In order to reveal the effect of pulsed UV irradiation on microorganism inactivation, inactivation efficiency of E. coli was compared between pulsed UV irradiation and continuous UV irradiation using deep UV-LED. For pulsed irradiation, following two methods were used; switching electric current and blocking UV by rotating shutter. Inactivation efficiency per time did not differ between continuous UV and pulsed UV by rotating shutter. However, pulsed UV by switching electric current showed higher inactivation efficiency than continuous UV. It is suggested that the reason of the higher inactivation efficiency was the improvement of luminous efficiency caused by temperature fall of the LED.