Pork Small Intestine
Pork Small Intestines are 15 to 20 meters long on average, and their diameter and strength vary according on the breed of animal and the type of feed taken. Casings are now processed using new cleaning processes that do not require fermentation.
The intestines are first crushed between rollers of a mucous crusher and then slimed, i.e. passed between a set of rollers or strippers to remove mucosa and other unnecessary layers of the intestinal wall (both muscle layers and serosa), leaving only the submucosa, after removal of fat and mesentery (“running”), cleaning and removal of the intestinal contents (“stripping”) by machine or by hand. The slimed intestines are graded (inflated with air or water), salted with 40% salt, and stored until they are needed.
Fermentation has traditionally been used to digest the intestines of pigs (and especially sheep). Fermentation allows them to slime by hand rather of using machinery. The procedure is as follows: the casings are turned inside out and soaked in water at 20° to 24°C overnight or until the mucosa and muscle layers become sufficiently delicate for manual removal (“sliming”). The processed pork rounds are generally constituted of solely the submucosa layer as a result of this treatment; the connective tissue-rich submucosa is not loosened, and the end product is mechanically strong.
Pig rounds are packaged in hanks of 100 yards (300 feet or 91.4m), each containing 15 to 20 pieces measuring around 18 feet (5.5 m). Pig casings are classified as narrow (28 mm and under), narrow medium (28 to 32 mm), normal medium (32 to 35 mm), medium (35 to 38 mm), broad (38 to 42 mm), and extra wide (38 to 42 mm) based on their diameter (42 mm and over). Fresh sausages, chorizos, and frankfurters are all made with pig casings.