Mathematical simulation of liquid food pasteurization using far infrared radiation heating equipment

In this study, pasteurization equipment using far-infrared radiation (FIR) was developed for liquid food. The temperature was measured at various conditions to investigate the heating effect. With the liquid food passing down an angled trough and FIR applied from above, the temperature changed with the radiation intensity (electricity supplied), the angle of the incline, and the flow rate. As the liquid film became thinner, the temperature could be heated to nearly 80 degrees C. The pasteurization effect was verified using lactic acid bacteria as the target microorganism; the heat resistance of the bacteria was measured, the death of bacteria was confirmed, and the effectiveness of the equipment was verified. Furthermore, a mathematical model for FIR pasteurization was developed using a heat transfer equation and thermal death equation. The simulation could make predictions about temperature and the viable count of bacteria that compared very well with the experimental results. Moreover, the model simulated the change of temperature and viable count of bacteria at different flow rates, and showed that it is possible to sterilize at low temperatures with this equipment. (C) 2011 Elsevier Ltd. All rights reserved.