A method of use of a sampling device for sampling through a sampling valve, the method comprising the steps of: providing a sampling device comprising a sample container with a flexible wall and with an interior, a coupling member, such as a socket, for coupling to a sample outlet connector, and a conduit connection between the coupling member and the interior of the sample container, at least the interior of the sample container being sterile, the conduit connection comprising a sterility protection ensuring the sterility of the interior of the sample container, said sterility protection being in the form of a three-way valve (25; 25') between the coupling member and the sample container, the three-way valve (25; 25') having a connection (33a, 23) to the coupling member, a connection (33b, 23) to the sample container and an outlet (43; 71), and the three-way valve (25; 25') being, before use, in a closed position in which it bars access to the interior of the sample container, thus closing the sample container; connecting the coupling member with the sample outlet connector of a sampling valve; flowing cleaning fluid through a valve chamber of the sampling valve, through the sample outlet connector, the coupling member and the conduit connection (33a, 23) to the three-way valve (25; 25') and out through the outlet (43; 71) of the three-way valve (25; 25'); opening the three-way valve (25; 25') to provide an open passage through the conduit connection from the sampling valve to the interior of the sample container; and opening the sampling valve to allow a desired quantity of the contents of a container, on which the sampling valve is mounted, to be collected in the sample container. providing a sampling device comprising a sample container with a flexible wall and with an interior, a coupling member, such as a socket, for coupling to a sample outlet connector, and a conduit connection between the coupling member and the interior of the sample container, at least the interior of the sample container being sterile, the conduit connection comprising a sterility protection ensuring the sterility of the interior of the sample container, said sterility protection being in the form of a three-way valve (25; 25') between the coupling member and the sample container, the three-way valve (25; 25') having a connection (33a, 23) to the coupling member, a connection (33b, 23) to the sample container and an outlet (43; 71), and the three-way valve (25; 25') being, before use, in a closed position in which it bars access to the interior of the sample container, thus closing the sample container; connecting the coupling member with the sample outlet connector of a sampling valve; flowing cleaning fluid through a valve chamber of the sampling valve, through the sample outlet connector, the coupling member and the conduit connection (33a, 23) to the three-way valve (25; 25') and out through the outlet (43; 71) of the three-way valve (25; 25'); opening the three-way valve (25; 25') to provide an open passage through the conduit connection from the sampling valve to the interior of the sample container; and opening the sampling valve to allow a desired quantity of the contents of a container, on which the sampling valve is mounted, to be collected in the sample container.