Plant for pasteurising foodstuffs or beverages filled into closed containers by way of a process liquid , wherein the plant comprises: at least one heating zone , at least one pasteurising zone and at least one cooling zone , which are arranged successively in a conveying direction of the containers , each of the zones being assigned a sprinkling device for discharging the process liquid and a collecting region for receiving the discharged process liquid, conveying means for conveying the containers in the conveying direction through the at least one heating zone , the at least one pasteurising zone and the at least one cooling zone , a first heat exchanger which feeds heat from a heat source , such as from a steam or hot water source, to the process liquid from a collecting region of the at least one pasteurising zone and for this purpose has a line connection to the one collecting region of the at least one pasteurising zone and to feeds to the sprinkling devices of the at least one heating zone via a pressure-closed heating line system , a second heat exchanger coupled to a cooling plant, such as a cooling tower, for cooling the process liquid from the collecting region of the at least one cooling zone and, for this purpose, has a line connection to the one collecting region of the at least one cooling zone and feeds to the sprinkling devices of the at least one cooling zone via a pressure-closed cooling line system , a heat pump comprising a condenser and an evaporator , wherein the condenser is designed to supply additional heat to the process liquid in the heating line system by means of the condenser and wherein the evaporator is designed to additionally cool the process liquid in the cooling line system by means of the evaporator . at least one heating zone , at least one pasteurising zone and at least one cooling zone , which are arranged successively in a conveying direction of the containers , each of the zones being assigned a sprinkling device for discharging the process liquid and a collecting region for receiving the discharged process liquid, conveying means for conveying the containers in the conveying direction through the at least one heating zone , the at least one pasteurising zone and the at least one cooling zone , a first heat exchanger which feeds heat from a heat source , such as from a steam or hot water source, to the process liquid from a collecting region of the at least one pasteurising zone and for this purpose has a line connection to the one collecting region of the at least one pasteurising zone and to feeds to the sprinkling devices of the at least one heating zone via a pressure-closed heating line system , a second heat exchanger coupled to a cooling plant, such as a cooling tower, for cooling the process liquid from the collecting region of the at least one cooling zone and, for this purpose, has a line connection to the one collecting region of the at least one cooling zone and feeds to the sprinkling devices of the at least one cooling zone via a pressure-closed cooling line system , a heat pump comprising a condenser and an evaporator , wherein the condenser is designed to supply additional heat to the process liquid in the heating line system by means of the condenser and wherein the evaporator is designed to additionally cool the process liquid in the cooling line system by means of the evaporator . <EOS>