A film-forming collagen concentrate is provided containing at least 18% by weight dry matter. At least 50% by weight of the protein of a homogeneous suspension produced from the concentrate in a 0.15 molar aqueous sodium dihydrogenphosphate buffer having a pH of 7 and a calculated dry matter fraction of 0.5% by weight may be separated as sediment by 15 min centrifugation at 1780 RFC and 15° C. A process is also disclosed for producing a collagen-concentrate-containing food casing that includes (a) producing an aqueous collagen mass； (b) concentrating the aqueous collagen mass until it has a solids fraction of 18% by weight or more； (c) admixing the concentrate with dilute acid to obtain a (co)extrudable or castable collagen mass； (d) coextruding or casting the collagen mass to from a casing； (e) solidifying the casing and, optionally, (f) drying the casing.
