In the design of thermal food process operations, the temperature in the slowest heating zone
(SHZ) and the thermal center of the food during the process must be known. Traditionally this
temperature is measured using thermocouples. The placement of thermocouples to record the temperature
at various positions in a container during heating disturbs the flow patterns, causing errors
in the measurements (Stoforos and Merson, 1990). Also, it is difficult to measure the temperature at
the SHZ because this is a nonstationary region, which keeps moving during the heating progress, as
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