Abstract: A closure includes: (a) a base attached to an opening of a container, a conduit extending therethrough in fluid communication with contents of the container, a tubular spout guide defining a portion of the conduit, an annular deck extending radially inwardly from an inner circumferential surface of the base defining a central orifice in fluid communication with the conduit,;and (b) an annular spout mounted to the tubular spout guide for reciprocation between an open position and a closed position, the spout including (1) an annular wall and (2) a plug positioned radially within the annular wall; the plug has annular, outer circumferential seal surface that is received within, and plugs the central orifice of the deck; a portion of the seal surface of the plug is axially recessed or flush with the annular wall of the spout; the seal surface has either a cylindrical shape or a frustoconical shape.