A one-way valve is connectable in fluid communication with a fluid-receiving chamber, such as a dilution chamber or a mixing chamber for diluting or mixing a perishable food product, such as a milk product or chocolate product, and forming a substantially fluid-tight seal therebetween. The valve comprises a relatively rigid valve seat, and a relatively flexible valve member overlying the valve seat and forming an axially-elongated, normally-closed valve opening therebetween defining an inlet at one end of the valve seat, an outlet at an opposite end of the valve seat, and an axially-extending seal therebetween that forms a fluid-tight seal between the inlet and outlet of the normally-closed valve opening. An axially-extending valve body is radially spaced relative to the valve member and forms a space therebetween allowing fluid-flow therethrough for cleaning the valve and the fluid-receiving chamber. A seal is engageable with the fluid-receiving chamber and forms a substantially fluid-tight seal therebetween to seal the valve outlet and fluid-receiving chamber with respect to ambient atmosphere. The valve member is movable radially away from the valve seat in response to substance at the inlet to the valve opening exceeding a valve opening pressure to flow into the normally closed valve opening, through the outlet, and into the fluid-receiving chamber.