The method involves determining a value of a preparation chamber atmosphere and/or of an atmosphere surrounding a food preparation appliance (1) after loading a cooking product into a preparation chamber (4) or after introducing a lime removal and/or cleaning agent into the preparation chamber and/or after beginning a treatment program. Another value is determined from the former value, where the latter value is compared with stored values. The treatment program is conducted as a function of the result of comparing the latter value with the stored values.