A fuzzy logic-controlled thermal process for simultaneous pasteurization and cooking of soft-boiled eggs

A fuzzy logic-based design of control for a unique thermal process in the food industry is presented. Products of the thermal process are pasteurized soft-boiled eggs. The function of temperature vs. time is unique in its shape and in its required precision, since the constraints of pasteurization and cooking of soft-boiled eggs are technically contradictory. Both processes can coexist only in a quite narrow temperature range, which is a nonlinear function of egg processing time. Precision in temperature control is essential. The thermal process is implemented in an apparatus that presents a novelty on the market of industrial kitchen appliances.A precondition for the present work was simulation of thermal energy propagation in hens' eggs of different sizes and ages. A function of temperature vs. time for the media in which eggs are immersed was defined. The function is piecewise linear in time, with horizontal and near vertical sections and abrupt transitions between them.The process is patented and the quality of pasteurization is certified by the corresponding institutes. The result is pasteurized soft-boiled eggs for consumption in hospitals, schools and hotels. The presented fuzzy control implementation of the thermal process meets the requirements, and thus the implication is that the design and implementation of temperature control based on fuzzy logic is suitable for processes where precision is required.