(1) Cellulose casings. Cellulose casings are manufactured as a by-product
of the cotton industry. When used for sausage produced in a plant under the
supervision of the USDA, these casings must have an ingredient statement printed on
them. The statement itself should stretch proportionately with the casing and remain
legible. Casings have varying degrees of stretch, a high stretch is 40 to 60 percent of
the original size, and a standard stretch is 20 to 30 percent of the original size. The
casings for small sausages are formed from large sheets of cellulose. They are made
into tubes approximately 50 feet or longer and are then compressed into lengths of 10
to 12 inches by shirring. This process facilitates storing and handling.
(2) Fibrous casings. Fibrous casings are the strongest and most uniform of
all casings. The casings are made from a paper base and impregnated with cellulose.
They are the most suitable if the product is to be sliced. These casings are used for the
dry or semidry sausage; fibrous-type casings must be used, since they are the only
artificial casings that adhere to the meat as it shrinks during dehydration.
(3) Plastic casings and wrappers. Plastic casings or wrappers are used for
products that have been completely processed. Due to the low rate of oxygen and
moisture transmission, these casings are not suitable for products that require smoking
or cooking after stuffing.
(4) Cloth casings. Occasionally, casings made from cloth are used for
b. Natural Casings. Natural casings are better than artificial casings because
they are edible, permit more smoke and moisture transfer than artificial casings. These
casings are the intestines of sheep, cattle, or hogs; the urinary bladder from calves and
cattle; and the stomach of hogs.
Because pork is a constant component of dry sausage and because sausage is
eaten without further processing, special consideration must be given to the destruction
of the parasite Trichinella spiralis. The reservoir and source of infection for trichinosis is
chiefly pork and pork products. There are several methods of destroying the parasite,
such as heating to 137F, drying and curing sausage meat in a relatively high
concentration of salt, and by freezing with specific times and temperatures. In the
quick-freezing method, all parts of muscle tissue of pork or product containing pork
tissue will be subject continuously to a temperature not higher than one of those
depicted in Table 6-1. The duration of the freezing period is dependent upon the
thickness of the meat or the inside dimensions of the container.
a. Group 1. Group 1 consists of product in separate pieces not exceeding 6
inches in thickness, or arranged on separate racks with layers not exceeding 6 inches in
depth, or stored in boxes or crates not exceeding 6 inches in depth, or stored as solidly
frozen blocks not exceeding 6 inches in thickness.