James G. Lyng

　　UCD Institute of Food and Health, University College Dublin, Belfield, Dublin 4, Ireland.

　　Ultrasound, encompasses sound which has a frequency above the threshold of human hearing. In its low intensity form it is non-invasive and has many applications in areas such as sensor technology (e.g. liquid/slurry flow, process control (e.g. renneting) and product (e.g. meat, cheeze) characterization) and also imaging (e.g. food packaging seal defects, agglomeration of milk products), to name but a few examples. This ‘mild’ form of ultrasound has no impact on the transmitting media which puts it in contrast to high intensity ultrasound (i.e. power ultrasound) a form of ultrasound with higher intensity (and generally lower frequency) which capable of inducing changes in transmitting matrices by physical (e.g. mechanical movement, localised pressure and temperature increases) and chemical (e.g. sonochemical reactions) means. Many of these changes relate to the phenomena of cavitation.  Power ultrasound has great potential in food preservation as a means of microbial inactivation. Furthermore, physical phenomena and associated micro streaming can also be used to enhance heat transfer (with potential to accelerate heating and/or cooling) and also mass transfer in areas such as extraction (e.g. polyphenols from plant matrices), impregnation (e.g. brine diffusion in meats), osmotic dehydration (e.g. fruits and vegetables) and cleaning (e.g. crab cooking). Since the year 2000 there has literally been an exponential increase in the number of scientific publications investigating the potential of Power Ultrasound in Food Processing with over 960 publications now existing in the literature. The presentation associated with this abstract will attempt to provide a general overview of the current state of the art in the area in Power Ultrasound in Food Processing, choosing some examples for more detailed overview. It will also consider the current status of power ultrasound in terms of commercial uptake while also attempting to identify potential barriers to the uptake of this technology by industry.