In a shell-and-tube heat exchanger (W) comprising a casing tube (1) and at least one inner tube (3) for treating liquid food products, optionally also with a product/product flow guidance, comprising at least one thermal-expansion compensating device (K) for the casing and/or inner tube (1, 3), with the compensating device (K) having a surface (12) which can be contacted by the product to be treated, said surface is provided, on a bellows integrated into the casing and/or inner tube (1,3), with a plurality of relatively wide folds (F1, F) which extend around the tube axis (X) and are of rounded cross- section, with the respective fold (F, F1) being configured with a radial depth (T) and an axial width (B) with a ratio of B : T of about 1 or more and to be cleanable on the product side in a hygienically irreproachable way.
