The invention relates to a steam injection module (1), suitable for a unit for the pasteurization or sterilization of liquid to highly viscous food products. A steam tube (2) passes through a product line section (3), transverse to the longitudinal axis, made homogeneously from a single material by cutting with no welded seams. This steam tube (2) exhibits steam outlet openings (7) within the product line section (3). The hot steam at about 150 degrees centigrade is injected into the flowing product through the steam outlet openings. The product line section (3) and this steam cube (2) are each fixed by fixing flanges (8, 8', 9,9') in the total line set of the unit.