Abstract: A method of packaging fluid or powdery products, in particular foodstuffs or beverages, in an essentially sterile manner in a packaging material in the form of a pouch of foil material having a filler opening closable by a closure cap, said method includes: providing a pouch whereby the closure cap can be placed in a first and second sealing position relative to the filler opening, whereby the closure cap is removable non-destructively from the filler opening in at least the first position; subjecting the interior of the empty substantially flat pouch having the closure cap in its first position to a germ-killing treatment; conveying the pouch having the closure cap in its first position and its interior already subjected to a germ-killing treatment to a filling plant; subjecting the exterior of the pouch having the closure cap in its first position to a germ-killing treatment; removing the closure cap from the pouch; filling the product into the pouch through the filler opening; and re-placing the closure ca