The intestine's other life — catgut, medicine, and feed industry

As an intestine technician you naturally think first of sausage production when you hear the word natural casing. But intestine as a raw material has a broader life than as sausage casing. According to the description of the apprenticeship the apprentices work among other things with processing animal intestines for both sausage production and the pharmaceutical industry — and historically the intestine has played a surprisingly large role in surgery.

§Catgut — suture from sheep intestine

Catgut is the name for a surgical suture material historically made from sheep small intestine — despite the name which likely comes from the English expression for cat intestine or from "cattlegut". Use of thread as suture in surgery is described as early as around 1500 BCE in the ancient Egyptian Papyrus Smith and throughout history people have tried many materials — dried intestines, tendons, skin strips and textile fibres — before catgut became the most widespread solution for many centuries.

Production required a very special process: the raw intestines had to be soaked and thoroughly cleaned, treated with disinfectant solutions and wound up before they were ready for use as suture thread. In other words, it was a form of very specialized intestine cleaning — just for a medical purpose instead of a food purpose.

§Why catgut has almost disappeared

Today catgut is rarely used as suture material anymore. This is due to several factors: the material loses around half its tensile strength within 2-3 days it causes more tissue reaction than modern synthetic sutures and — most importantly — there has been uncertainty about the risk of transmitting prion diseases like BSE/TSE from the animals especially sheep whose intestines are used in production. Several EU countries including France Germany Austria and Spain have therefore banned catgut sutures for use on humans.

§Pharmaceutical and feed industry today

Although catgut as suture material is on the way out the intestine's role outside the food industry does not disappear. Parts of the processing a gut technician learns — cleaning sorting and quality control — are also used when by-products from gut production go on to the pharmaceutical industry or to the feed industry. It is part of the broader thinking behind animal by-products: nothing from the animal should go to waste and different qualities and parts of the intestine can find different buyers depending on what they are suitable for.

• 01Food industry: sausage casings for human consumption — majority of production.
• 02Pharmaceutical industry: processed intestine products for purposes other than food.
• 03Feed industry: byproducts that do not meet food quality can go to feed.
• 04Historical: catgut suture from sheep intestine, today largely phased out in favor of synthetic sutures.

§From local craft to global industry

The broad use of intestine as raw material is part of the explanation for why Danish intestine processing today encompasses everything from small, specialized intestine cleaning businesses to large, international companies. An example is DAT-Schaub, a global Danish producer of natural and artificial intestine casing, which today is owned by Danish Crown. The company has roots back to 1893, when the German intestine company Schaub & Co. opened a branch in Esbjerg, and to 1913, when a group of Danish cooperative slaughterhouses founded their own intestine company, Danske Andelsslagteriers Tarmsalg (DAT). The two companies merged in 1972 to form DAT-Schaub, which today has production in Denmark and many other countries. The history shows that what began as a local residual product craft is today part of a global supply chain.

When you understand that the trade extends beyond the sausage counter – and that the same basic material can become anything from a frankfurter to historical surgical suture – it becomes clearer why quality control and sorting fill so much of your everyday. The same casing can end up very different places depending on what quality it has and it is your skill and judgment that helps determine that.