A machine (1) comprises: —a device (20) for handling a capsule (2); —a frame or a housing (10) covering the device (20), delimiting an opening (12) for passing a capsule (2) through the frame or housing (10) to the handling device (20) and having a curved cross-section (10′) about the opening; and —a barrier means (30) comprising a member (31a; 31b) movable from a closed position for preventing such capsule (2) from passing through the opening (12) to an open position for allowing such capsule (2) to pass through the opening (12). The member (31a; 31b) is movable between its closed position and its open position along a curve (31′) that is generally parallel to the curved cross-section (10′) of the frame or housing (10).