A sealing mechanism for a waste storage container includes a waste storage container that has a body, a lid and a cartridge adapted to be positioned in the body. The cartridge has a continuous length of storage film therein. The storage film emanates through a gap between a rim and a core tube of the cartridge and is folded down through a core opening in the core tube into an interior space of the body of the waste storage container. The sealing mechanism includes an actuator accessible from outside of the body, a gear assembly operably connected to the actuator, a retaining assembly that holds stationary a dispensed portion of the storage film in the interior space of the body during a twist-closure operation, and a plunger operably connected to the gear assembly.