Abstract: The invention relates to a method of surface dyeing of protein articles of food, such as meat, cheese, fish etc., particularly of protein casings used as outer coverings of food-stuffs. It consists in subjecting the protein products to the action of a dyeing substance comprising an aqueous solution of a wood-bark extract, advantageously of oak or birch bark. The protein product may be dyed: by immersing the product in the dyeing solution, by sprinkling the product with the solution or by contacting the product with an aerosol formed by spraying the solution of the extract. The dyeing process according to the invention may be applied both to raw casings and to casings filled with the food-mass in the form of batons.