A baby bottle (10) having a dispensing member (20) and a sealing membrane (14) disposed between the dispensing member (20) and an open end (15) of the container (10). A threaded collar (26) engages the open end and a shoulder (34) extends laterally adjacent an extent of the thread. The sealing membrane (14) includes ports (42) for communicating fluid therethrough. The sealing membrane (14) moves from a sealing position with a sealing surface (24) in bearing contact with the open end (15) and a dispensing position with the sealing surface (24) spaced apart from the open end for fluid flow through the ports (42). The sealing membrane moves in response to the shoulder (34) moving as the collar (26) is rotated and moved longitudinally outwardly relative to the end (15) by the camming action of the thread on the bottle (10).