DESIGN OF A LABORATORY-SCALE CONTINUOUS FLOW THERMO-ULTRASONIC REACTOR FOR RAPID PASTEURIZATION OF LIQUID FOODS

The goal of this proposed project is to convert the batch ultrasonic process that we recently developed to a continuous one for rapid pasteurization of liquid foods. The following specific objectives will be pursued:1. Designing, modeling, and building a continuous flow thermo-ultrasonic reactor;2. Investigating effects of thermosonication on Escherichia coli and Listeria monocytogenes in apple juice (pH 3.8-4), watermelon juice (pH 5.2-5.7), and carrot juice (pH 6.4-6.7) and a surrogate for psychrotrophic Clostridium botulinum spores in watermelon and carrot juices under different combinations of acoustic energy density and temperature;3. Examining effects of thermosonication on color, antioxidant activity, and total phenolic content in the three juices;4. Testing changes in the total plate count of microorganisms, color, antioxidant activity, and total phenolic content in thermosonicated juices during 28 d of storage at 4 °C and changes in the total plate count of microorganisms during storage under a temperature abuse condition.