Abstract: Packages include a bottom foil having spaced nests formed therein and a cover foil. At least the bottom foil is permeable to radiation so that it may be irradiated on one side with a source of radiation following a filling station during movement of the packages through a packaging machine. The intensity of the radiation allowed to pass through the bottom foil is measured by a radiation receiver having an active receiving surface which overlies the filler material and which surface is greater than the surface of the filler material facing it. The radiation through the bottom foil casts filled nests onto the receiving surface. The shadow of a nest inappropriately filled differs from a shadow of the nests appropriately filled with the filler material. An apparatus is triggered for sorting out an inappropriately filled nest by starting signals of a receiver whenever the amplitude thereof fails to reach a predetermined value.