Biblical and rabbinic legislation permits certain foods for consumption. These are referred to as kosher ('fit'). Other foods, however, are prohibited. These include meat from birds and animals which are unclean or not ritually slaughtered; certain parts of animals (such as the sinew of the hip); meat and milk products eaten together; and any kind of fish that does not have both fins and scales. Jewish sources also deal with the preparation of food: for example, since Jews may not consume blood in any form, all meat must be soaked and salted before it is eaten. Although no reason is given in Scripture or rabbinic literature for these regulations, various explanations have been given, among them that dietary restrictions in themselves regulate holiness in everyday life, encourage self-discipline, keep Jews separate from gentiles, and protect the community from disease.