PURPOSE: To prevent the intrusion of microorganisms from a flow passage connected to an open end by providing a mechanism having the antimicrobial effect to lower the propagation of the microorganisms in at least a part of the flow passage.

CONSTITUTION: Pasteurized or sterilized liquid is discharged through the flow passage 1 to the outside. The discharge is stopped by a valve 3 or the like installed before the mechanism 2 having the antimicrobial effect. The liquid remaining in the flow passage flows out mostly from the open terminal 4 of the flow passage 1 even up to the valve 3 by gravity fall, etc., without stagnating when the discharge is stopped. The sticking, propagation, etc., of the microorganisms remaining in the slightly remaining liquid and the microorganisms intruding from the open terminal 4 are suppressed by the mechanism 2 which is applied in the form of a film on the inside surface of the flow passage 1 and has the antimicrobial effect, by which the contamination of the inside of the flow passage 1 by the microorganisms from the outside world is prevented. The mechanism having the antimicrobial effect includes the mechanism constituted by installing a thin circular tubular structure of a high polymer molded after being mixed with various antimicrobial agent or metal, etc., into the flow passage, the mechanism constituted by applying a coating material mixed with the antimicrobial agents in the flow passage, etc.