In the second step, focus was on the efficient and accurate estimation of the ten parameters of the extended cardinal model that describes the combined effect of temperature, pH and water activity on the microbial growth rate. Again, equidistant level selection is compared to a D-optimal (based) experimental design. In addition, a full factorial and a Latin-square approach are evaluated. From the simulation
case studies presented, it can be stated that all parameters can be equally well defined from an equidistant design as from a D-optimal-based design. In addition, reducing the experimental load by constructing a Latin-square design does not hamper the parameter estimation procedure. This work confirms the observation of a previous study, i.e., for complex cases a Latin-square design is an attractive
alternative for a full factorial design as it yields equally accurate and reliable parameter estimates while
reducing the experimental workload.