To find a good equilibrium between quality and margin of safety of minimally processed foods, often various hurdles are used. Quantification of the kinetics should be used to approach an optimum processing and to select the main aspects. Due to many factors of which the exact quantitative effect is unknown (uncertainty) and the often large (biological) variability, this is not a straightforward and easy procedure. For describing the kinetics one can start by describing the development in time (primary models), followed by models describing the parameters of the primary models as function of process variables (secondary models). Due to the complexity and large variability and uncertainty, it is best to start process analyses globally, using simple kinetic models. Various types of primary and secondary models will be commented upon and some criteria for model choice will be given. Especially, if dimensionless numbers can be defined, then these can be used for a structured analysis, clearly quantifying main aspects. Important points for the development of models and interpretation of modelling results will be presented.