The invention is characterized in that the straw body (1) is consisting of two or more segments, which are attached together with connection (5) and that the straw body (1) on its both ends has a cross-slit valve (2, 3) closure and the valves (2, 3) and the straw body (1) are integrated by molecular adhesion. The inlet and outlet valves (2, 3) are of a slit type. The straw body (1) is preferably made of a thermoplastic material and the valves (2, 3) are preferably made of elastomer material. The edge of the straw body (1) is shaped to enable larger surface of the connection between the straw body (1) and the valve (2, 3). The said shape is preferably a groove (8). On the wall on the end of the straw body (1) a tongue-shaped groove (9) is formed on the surface side.
