Inactivation of microorganisms by low-frequency high-power ultrasound: 1. Effect of growth phase and capsule properties of the bacteria

Different bacteria were treated with high-power low-frequency ultrasound. The log reduction of some bacteria increased with increasing ultrasound power. Bacterial particle size distributions were measured and TEM micrographs were taken. E. aerogenes was more sensitive to ultrasonication in exponential growth phase. Bacterial cells with capsules were more resistant to ultrasound treatment.