A unit for carrying out an operation on a container fillable with a pourable product is disclosed. The unit comprises: a first area; a second area; at least one operative head, which is adapted to carry out the operation; at least one gripping device for gripping the container and which is movable between a rest position, in which the at least one gripping device receives or discharges the container; and an operative position, in which the at least one gripping device sets the container in a position in which the container undergoes the operation. The unit further comprises: a movable element, which is operatively connected to the at least one gripping device for moving the at least one gripping device between the rest position and the operative position, and which comprises a portion movable between the first area and the second area; and a bellow.

A sterilization method includes a sterilizer supplying step of supplying a sterilizer to a sterile zone conveyor while the sterile zone conveyor is being rotated, and a sterile water supplying step of supplying sterile water to the sterile zone conveyor while the sterile zone conveyor is being rotated.