Processing of Animal Intestines

processing of the intestines (intestinal raw material) of farm animals slaughtered for meat to obtain intestinal products (finished products). Intestinal raw material also includes the esophagi and urinary bladders of cattle and swine, which are structurally similar to the intestines. The raw material obtained from a single animal constitutes the intestinal complex. Finished intestinal products are used mainly as casings for sausages. Some 55 percent of the sausage casings are made from animal intestines; the rest of the casings are made from polymeric materials. Nonstandard finished products are used to manufacture cord and sutures. Surgical thread (catgut) and strings for musical instruments and tennis rackets are made from finished sheep products. Processed bladders are also used in the dry goods industry, and serous membranes from the cecum are used in the perfume industry to seal bottles.The use of animal intestines to make thread for sewing footwear and fur clothing and to manufacture strings for musical instruments has been known from very ancient times. The development of the processing of animal intestines is related to the appearance of sausage products. In Russia, the industry dates back to the 16th century. In the 19th century, the Uglich and Moscow sausage-makers also processed intestines. It was a cottage craft in prerevolutionary Russia and was carried on under such unsanitary conditions that even with the low health standards prevailing at that time it was prohibited in slaughterhouses. With the introduction of automation and modern methods, shops for processing intestines were set up in the main work buildings of meat-packing plants. Intestines are also handled in intestinal processing workshops, which receive the raw material from small slaughterhouses that do not themselves process intestines.

The mucous membrane is the weakest of the four layers that make up the intestines, and it is removed when processing almost all kinds of raw material. The submucous layer is the strongest and it is always left intact. The muscular and serous layers are removed or left, depending on how tough they are (which is determined by the section of the intestine) and the purpose of the finished product. The processing of animal intestines includes the following principal operations: separation of the intestinal complex into parts, removal of the intestinal contents and thorough washing of the intestines, fat extraction (skimming), and removal of the mucous membrane (stripping) and other superfluous layers. The mechanized assembly lines used in the processing of animal intestines ensure high output per man-hour and maintenance of hygienic conditions. The processed intestines are cooled with water, graded according to quality and size (diameter, length), tied in bundles, and preserved with table salt or by curing. Slaughterhouses that do not process animal intestines preserve by corning incompletely processed, cleaned, and washed intestines after obtaining the raw material. The final stage of processing takes place in special intestinal processing shops. Salted intestinal finished products are packed in wooden barrels, and dry intestinal products are packed in wooden boxes or barrels for dry matter. Salted intestinal finished products can be stored in refrigerated warehouses at 0°-10°C for one or two years, and dry intestinal products can be kept in dry storage areas at a relative humidity no higher than 65 percent for up to a year.