Abstract: A plant for treating heat-sensitive fluid foodstuffs, such as whey protein concentrate and cheese milk, is provided. The plant comprises: an infusion chamber having an outlet opening, in which the fluid foodstuff is subjected to a heat treatment by a feeding of steam therein; a vacuum chamber having an inlet opening in communication with the infusion chamber for removing water from the fluid foodstuff; and a positive-displacement pump connected to the outlet opening of the infusion chamber and connected to the inlet opening of the vacuum chamber in such a manner that during operation of the plant a pressure drop applies across the pump in the flow direction of the fluid.