Abstract: When placing block carton linings in freezing frames it is important that the existing corner flaps (20, 27) on the carton insertion are placed externally on the adjoining side panels (8), so that they cannot be frozen when sticking into the material filled into the lined freezing frame. During a fast mounting of the block carton it may be difficult to perceive whether these corner flaps are placed inwardly or outwardly of the adjoining carton sides, since they visibly will become indistinguishable in relation to the surroundings. By the invention this will be changed, so that the inwardly facing sides of the corner flaps (20, 27) are made with a surface characteristic, e.g. a distinct signal colour, which is deviating in such a way from the outlook of the rest of the inside of the carton, that a faulty placing of the corner flaps will be discovered instantly by sight.

Abstract: Carton liners are used in freezing frames for the preparation of large frozen blocks of fresh food material, e.g. fish fillets. The liners have a lid with skirt flaps to be closed upon filling of the liner, and care should be taken that the lid flaps be located at the outsides of the liner walls inside the freezing frame, as they may otherwise be embedded in the material to be frozen and thus disturb the regularity of the frozen block material. The same applies to corner flaps which, already by the mounting of the liner, should be folded to assume an exterior position. According to the invention, in order to ascertain a correct mounting and closing of the liners once they have been removed from the freezing frames, such liners are used which are provided with printed marking on those outside area portions that are to be covered by exterior liner/lid flaps, and the closed liners are inspected for detection of any visible marking, which will be indicative of a potentially defect block product.