Casings have been utilized throughout the years in the production of sausage and processed meat products. Casings have been referred to as the oldest form of packaging materials for sausage. Casings determine the final size and
shape of the sausage product. Casings serve as processing molds, containers during handling and shipping, and as merchandising units for display. In years past, sausage production was limited to the amount of available animal intestines. With the development of collagen, fibrous and cellulose casings the production of sausage is only limited by the availability of raw materials. Sausage casings have evolved from old orld innovation and applied to today’s high paced processed meat production. Casings are made of two basic materials, cellulose or collagen. Five specific casings are generally used in the production of sausage products – animal, regenerated collagen, cellulose, fibrous, and plastic casings.
Natural casings come from the gastrointestinal tract of animals. Natural casings are made from the submucosa, a largely collagen layer of the intestine. The fat and the inner mucosa lining are removed. Natural casings have the advantages of traditional appearance, traditional texture and cooking performance that is expected of sausage. A few disadvantages are noted as decreased machinability, reduced uniform weight or length, and cost. Natural casings produced from the intestines of cattle, hogs, and sheep.
The three most used beef casings are: beef bung caps, beef rounds, and beef middles. The beef casings come in a variety of sizes depending on which type is used (e.g. bung caps, rounds, or middles.). Beef bung caps are used for large diameter sausage such as bologna and salami. Beef rounds have the characteristic ring or round shape that are used in the production of ring bologna and polish sausage. Beef middles can be sewn so that the final product will have a uniform diameter and uniform length. Beef bladders can also be used in the production of large diameter sausages such as specialty sausage (souse or head cheese). Bladders are the largest diameter of casings from cattle and are oval in shape.