The present invention proposes a device for preparing a nutritional composition by supplying water to ingredients provided to the device comprising a pump (2) being connected to an integrated or external water supply(1), a water discharge head (4) designed for providing water to a cartridge containing ingredients (7) for interaction between water and the ingredients in the cartridge (7), wherein the pump (2) and the water discharge head (74) are in water communication via a water flowpath (50), whereby the pump can supply water under pressure through the water flowpath, a rigid filter assembly (20) comprising at least one antimicrobial filter membrane (30) and filter enclosing means (40a, 40b), wherein the filter assembly (20) and the filter enclosing means (40a, 40b) are complementary configured such that the filter assembly (20) is insertable into the filter enclosing means (40a, 40b) across the water flowpath (50) in a fluidtight manner before the water discharge head (4), and is removable from the filter enclosing means (40a, 40b).
