A process for conducting cleaning operations at predetermined time intervals in a chamber or container of a fluid-receiving device of a foodstuff-processing apparatus first comprises receiving a first fluid in the chamber or container. Then, first and second degrees of cleaning are determined at first and second moments in time, respectively. Then, a first difference between the first and second degrees of cleaning is determined. In a first case, in which the second degree of cleaning lies below a first limit value, the action duration of the at least one cleaning agent during at least one subsequent cleaning operation is set depending on the first degree of cleaning. In a second case, in which the second degree of cleaning lies above the first limit value, a greater amount of cleaning agent is supplied and/or the time interval between two subsequent, successive cleaning operations is shortened.