A machine is provided including a receptacle for loading waste, a shredder, and a pusher to push waste toward the shredder. The receptacle has a constant cross-section between a waste loading opening and a communication opening with the shredder, and the pusher is a plate translatable in the receptacle, parallel to the axis along which the receptacle has the constant cross-section. The plate is dimensioned such that only an interstice exists between the plate edge wall and the walls defining the receptacle； the plate is movable between a withdrawn position able to be freed from said waste loading opening, and an end-of-travel position situated near the communication opening. The machine comprises a sealing gasket movable between a retracted position, which does not hinder the mobility of the plate in the receptacle, and a sealing position, which produces, in the end-of-travel position of the plate, sealing between the plate and the receptacle walls.
