A hygienic food product to food product heat exchanger (1). The heat exchanger (1) has an elongated and hollow housing (4), a metal tube plate (6) arranged at each of the opposite ends of the elongated housing (4) for defining a closed interior space (10) inside the elongated and hollow housing (4), a plurality of tightly spaced metal tubes (2) axially extending between the tube plates (2) with the ends of the tubes being received in correspondingly tightly spaced holes the tube plates (6) or with the lumen of the tubes being aligned with said correspondingly tightly spaced holes in the tube plates. The metal tubes (2) are sealingly secured to the metal tube plates (6) by a welding joint (20) on the inwardly facing side of the tube plates (6).