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.