Operating a pasteurization plant containing a primary circuit for a medium to be pasteurized and a secondary circuit, comprises: flowing the medium to be pasteurized into the primary circuit and flowing a heating medium into the secondary circuit； discharging the medium to be pasteurized from the primary circuit by using a fluid, which is introduced into the primary circuit； stopping the flow of the fluid in the primary circuit after the primary circuit is filled with the fluid； and maintaining the flow of the heating medium in the secondary circuit. Operating a pasteurization plant containing a primary circuit for a medium to be pasteurized and a secondary circuit, where the secondary circuit is used as a heating circuit to heat the medium to be pasteurized in the primary circuit, comprises: flowing the medium to be pasteurized into the primary circuit and flowing a heating medium into the secondary circuit； discharging the medium to be pasteurized from the primary circuit by using a fluid, which is introduced into the primary circuit； stopping the flow of the fluid in the primary circuit after the primary circuit is filled with the fluid； and maintaining the flow of the heating medium in the secondary circuit after stopping the flow of the fluid (water or the medium to be pasteurized) in the primary circuit, up to and after a resumption of the flow of fluid in the primary circuit. An independent claim is also included for the pasteurizing plant comprising the primary circuit and the secondary circuit, in which a controller is provided to carrying out the above operation.
