Journal article

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

Shengpu Gao, Gillian D Lewis, Muthupandian Ashokkumar, Yacine Hemar



The aim of this study was to determine the effects of high-intensity low-frequency (20 kHz) ultrasound treatment on the viability of bacteria suspension. More specifically, we have investigated the relationship between the deactivation efficiency and the physical (size, hydrophobicity) and biological (gram-status, growth phase) properties of the microbes. Enterobacter aerogenes, Bacillus subtilis, Staphylococcus epidermidis, S. epidermidis SK and Staphylococcus pseudintermedius were chosen for this study owing to their varying physical and biological properties. The survival ratio of the bacteria suspension was measured as a function of the ultrasound power (up to 13 W) for a constant sonica..

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University of Melbourne Researchers


Awarded by University of Auckland

Funding Acknowledgements

S. Gao is supported by a New Zealand China Food Safety Scholarship, funded by the New Zealand Ministry of Foreign Affair and Trade. YH and MA thank the University of Auckland for the award of the Distinguished Visitor Award (Project number 3702372).