An apparatus for sealing and tapping containers for pressurized liquids such as beer kegs and the like including a resilient valve plug mounted in the tap hole of a keg and tap head removably mounted on the keg having an inner liquid delivery tube and an outer fluid supply tube extending downwardly through the valve plug into the keg to allow pressurized fluid to be supplied to the keg through the fluid supply tube and liquid to be withdrawn from the keg through the liquid delivery tube. The plug has integral valve means arranged to seal against the outer fluid supply tube when the head is mounted on the container, and which is adapted to close and seal the container when the head is removed.