Innovative Ultrasonics specializes in process development, engineering design, installation and equipment in the area of high-powered ultrasonics for new and existing industrial applications.
Microbial Inactivation
Antimicrobial effects can be generated by high power ultrasound. These are generally attributed to the effects of cavitation and the extreme pressure variations generated. Whilst most microbes may be able to withstand elevated pressures, they cannot withstand the rapidly alternating pressures produced during cavitation. In addition, some highly reactive radicals such H2O2 can be generated in aqueous media during cavitation, which may increase the antimicrobial effect of the process. Ultrasonic treatment is also likely to increase cell permeability to these compounds as mechanical disruption also occurs. Generally larger cells are more sensitive to ultrasonic treatment, and rod-shaped bacteria are more sensitive than coccoid cells. Gram negative cells are more sensitive than Gram positive cells, anaerobes more sensitive than aerobes. Spores are generally resistant. Other characteristics also influence antimicrobial inactivation produced by ultrasound - the age of the culture (actively growing cells are more sensitive than stationary phase cells), the treatment menstruum (temperature, pH, protective effects from salt, sugar, fat), etc.
As a stand-alone process, high power ultrasound can produce pasteurisation effects in food matrices, however these are unlikely to be sufficient to be commercially viable. The technology can act as an adjunct to processes such as heat to provide effective pasteurisation at lower temperatures than would be used with heat alone. This may allow greater preservation of flavours, colours and aromas in foods.