A programmable food service system including one or more food service devices and at least one data key. Each data key is provided with a data memory for storing program data corresponding to sequences of food service operations. Each food service device includes a programmable controller for controlling the food service device to carry out sequences of cooking operations. Each food service device includes a key aperture adapted to receive a data key and a data reader arranged to read program data from the data key memory. The program data is passed on to the programmable controller, thereby making the appropriate sequences of cooking operations available to the food service device.