AUTOMATED CONTROL OF HIGH-TEMPERATURE SHORT-TIME PASTEURIZATION

Cascade and multivariable control of a high temperature shot? time (HT ST) pasteurization system were tested and compared with the performanc e of single-loop feedback control. Multivariable control was implement ed on the basis of computations of product temperatures that yield equ ivalent lethality at a residence time of 15 s at 161 degrees F in the holding tube. Both cascade and multivariable controllers reduced produ ct temperature fluctuations and overshoot compared to single-loop feed back control. Multivariable control was based on on-line computation o f equivalent total lethality and it permitted operation at variable fl ow rates or at the most desirable temperatures for product quality and functionality. Copyright (C) 1996 Elsevier Science Ltd.