A spout (1) for a flexible pouch (100) for liquid food, such as fruit juices, yogurt, fruit or vegetable purees and the like, includes a tubular barrier (30) embedded in the tube (18), made of a material impermeable to atmospheric oxygen. The spout is made by molding equipment that includes a counter-mold (300) with fixed insert (302) and a movable skirt (304), slidably fitted on the fixed insert (302). The spout may be made by a production method in which, during the injection of a first oxygen permeable plastic material, the skirt (304) is moved, coming out of the barrier (30), which remains in a fixed initial position.