An electronic cash register system which comprises a control means having a cooking instruction transmission means (18) to transmit cooking instructions to a kitchen at suitable timing, whereby the cooking time, constituent materials and serve timing of each article can be controlled and efficient serving can be realized.

A high frequency cooker which detects a sound generated upon boiling of a material to be heated in response to the material being heated and switch as to a cooking mode in response to the detected signal of that sound. The cooker comprises a heating section for heating a material to be heated, a sensor for detecting a sound generated from the material to be heated upon boiling of the material to be heated, and a control section for controlling the heating section in response to the detected sound. The cooker can sense the sound of the material to be heated and can switch automatically from a cooking mode to a warm mode even by only making a single function selection. An optimum cooking state of the food can be maintained, and unnecessary power loss can also be prevented.

A roasting system includes a roasting chamber having an air infeed vent for receiving air and a flue for directing exhaust air from the roasting chamber. An air reconditioning system coupled between the air infeed vent and the flue eliminates the need for external venting. The air reconditioning system includes a heater for heating the air received in the roasting chamber through the infeed vent and an air filtering system. A fan draws the exhaust air from the roasting chamber, passes the exhaust air through the air filtering system and past the heater and then recirculates the filtered and reheated air back into the roasting chamber. Continuously filtering recirculated air allows the roasting system to be placed in retail coffee shops without requiring external ventilation or producing objectionable odors. By reusing the heated air from the roasting chamber, the roasting system is also more energy efficient than current coffee roasting systems and allows the roasting system to be operated in non-industrial locations.

A non-contact system and method is provided for effectively approximating the internal temperature of food being cooked upon a cooking surface of a cooking apparatus, such as a grill or griddle. Ultrasound or infrared, non-contact measurement devices may be directly installed onto the cooking apparatus, and in concert with a computerized monitoring/control system, are used to monitor the status of the food being cooked, or to control the heat input to the cooking surface using a feedback loop. The non-contact measurement devices may be permanently positioned above the cooking surface or may be mounted to arms that can be pivoted, or otherwise moved into position over the cooking surface.

A method and apparatus are described for determining the doneness of food during a cooking process. Ultrasonic signal are passed through the food during cooking. The change in transmission characteristics of the ultrasonic signal during the cooking process is measured to determine the point at which the food has been cooked to the proper level. In one aspect, a heated fluid cooks the food, and the transmission characteristics along a fluid-only ultrasonic path provides a reference for comparison with the transmission characteristics for a food-fluid ultrasonic path.