Abstract: The present work was based on a previously reported paper by Bhamidipati & Singh (1994), whose simulate the thermal time distribution (TTD) in a continuous sterilisation process. They applied a rigorous model for the governing equations of the system, i.e. continuity equation, momentum balance, energy balance and the calculus of the sterilisation value (Fo) for a given set of design and operating variables (tube radius, tube length, external temperature). Finally, the authors analysed the thermal time distribution curves for two different values of those variables. Here, we implement an integrated model in which the thermal time distribution pattern or Fo distribution (solved using implicit finite difference method) is incorporated into an external optimisation loop, which finally gives the optimum values for the variables. The optimisation problem is a Mixed Integer non Linear Program (MINLP) that includes an objective function that is a mathematical expression directly related to final product quality and subject to constraint imposed for a request Fo value in the coldest point. We illustrate the methodology by simulating the process with several typical fluid foods and comparing alternative objective functions.