The invention relates to a tubular, single or multi-layered polyamide and/or copolyamide-based food casing and/or including a polyamide and/or copolyamide-based inner layer. The water-vapour permeability of the casing is less than 30 g/m.sup.2 d. The surface tension of the inner side is greater than 28 dyne/cm.sup.2, preferably 35-45 dyne/cm.sup.2. The inside of the casing is impregnated with liquid smoke without the addition of a browning agent and the liquid smoke is practically totally absorbed by the casing. The casing is particularly useful as synthetic sausage skin, particularly for browing, cooking or roasting.