Casing

A very thin edible covering, either natural or some form of a synthetic, that is used to enclose ground meat and other ingredients that have been processed into a sausage product. Natural casings are usually made from the cleaned intestinal membranes of cows, hogs, lambs, and sheep. Lamb, sheep and hog casings are popular for breakfast sausage, fresh pork sausage and frankfurters, as well as other sausages. The large intestine provides a thick walled and fat membrane for use with meats that require increased storage time for seasoning and aging, such as some of the larger salamis and meat products. Smaller intestines are used for the medium to small-sized sausages and salami products while the colon, which is not as consistent in shape, is used for salamis and sausages that may be labeled as "crespone" or "crespo" meats.

Not all casings for meat products are natural casings. The alternative is to use cellulosic, collagen, fibrous, muslin, or synthetic casings. Cellulosic, which is made from solubilized cotton linters, is a strong casing that is commonly used for some of the various varieties of frankfurters. Collagen casings that are produced from animal parts (bones, cartilage and connective tissues), are common casings for use in sausage making. It is a uniform in texture, soft, and yet very durable for stuffing meats. Fibrous casings are very durable for use in stuffing coarse ground meats that are tightly packed into the casing. Semi-dry and dry sausages are most often made with a fibrous casing. Muslin casings are made with a fine weave cotton fabric that covers blood sausage, some bologna, liverwurst, and salami. Synthetic casings are generally those that are made from polymers formulated for use in the food industry. They are often used to encase some sausages in colored casings, such as white for liverwurst, clear for salami and red for bologna.