Investigation of Ultrasonic Parameters for Ultrasound Exposure of 36 kHz on E.coli Culture

Abstract

The extensive research work has been carried out on kill rate of E.coli with increased time of ultrasound exposure that depending upon the power, frequency and intensity. In contrast, the knowledge of ultrasonic parameters induced by ultrasound is rather limited, especially when it comes to the measurement of ultrasonic parameters with kill rate of E.coli. The present paper therefore, aimed to measure the ultrasonic velocity, attenuation coefficient and acoustical impedance with disruption of E.coli as a function of ultrasound exposure time at 36 kHz frequency. The ultrasonic velocity and attenuation coefficient were carried out by using novel Pulse Echo Overlap (PEO) technique. Spread Plate Techniques were used as a measure of microbial activity. It was observed that ultrasonic velocity and attenuation coefficient of E.coli were increased with initial exposure of ultrasound. This may be due to result of increased convection in E.coli culture by onset of stable cavitation. The onset of transient cavitations disrupts cells in suspensions with increased ultrasound exposure. Therefore, it was reported that ultrasonic velocity and attenuation coefficient decreases almost linearly with disruption of E.coli. The results of ultrasonic velocity and attenuation coefficient of E.coi were found in the right order of  magnitude and confirmed with A Zips and U Fast.