A plant for heat treating heat-sensitive fluid foodstuffs an infusion chamber in which the fluid foodstuff is subjected to a heat treatment by a feeding of steam, and a fluid foodstuff inlet connected to a plurality of openings at the top of the infusion chamber for creating a plurality of essentially downwardly directed separate fluid foodstuff jets. The infusion chamber has a bottom section configured to collect the fluid foodstuff from the jets. The bottom section has an outlet opening at the bottom of the infusion chamber for allowing the collected fluid foodstuff to exit the infusion chamber. The outlet opening is seamlessly connected to the inlet of a pump. A cooling jacket surrounds the bottom section for cooling the bottom section. The cooling jacket extends all the way down to the pump.