A method for durability treatment or sterilization of a pumpable material by high pressure treatment of the same in a high pressure press for killing and/or inactivating harmful microorganisms and enzymes in the material includes placing the pumpable material into a flexible bulk container with a larger volume than the end-user or consumer containers in which the material is intended to be packed, placing the bulk container in a high pressure press and subjected to high pressure treatment, removing the bulk container from the press. The material may be moved from the bulk container to end-user containers by arranging, in a sterile manner provided, connector on the bulk container, which, via a tube connects the interior of the bulk container with an emptying system, for the purpose of draining the pumpable material into the end-user or consumer containers, or into an intermediate storage tank.