UTILIZATION OF

INTESTINES

Dr. Irshad A, MVSc

Assistant Professor

Animal Casings

India is a major exporter of animal casings like cattle casings,

guts for animal casings, sheep casings and casings of other

animals.

Indian animal casings - high quality with excellent

calibration and shining colour .

The major destinations for exports are Vietnam, Italy, South

Africa, Portugal, Germany, Denmark and Spain.

Animal Casings

The country has exported 260.15 MT of Animal Casing products

to world for the worth of Rs. 19.32 crores during the year

2014-15.

Major Export Destinations (2014-15) : South Africa, Turkey,

Portugal, Lebanon andTunisia.

The individual products under this sub-head are as below:

Cattle Casings

Sheep Casings

Casings of other animals

Bladders and stomach of animals

Animal Casings Exports From India

Animal Casings

Intestine of domestic animals as slaughterhouse

by products

Non edible use: surgical catguts, sports guts, musical strings and

collagen sheets.

Edible use: When part of the processed intestine used as food

container called casing

CasingsDefinition:-

Alimentary tract of sheep, goat, cattle and pigs, sometimes

urinary bladder when used as food containers are called Casings.

Or

Casings are soft cylindrical containers used to contain sausage

mixes

Types of Casings

• Animal intestines derived from slaughtering

Natural

origin

• Cellulose,

• Collagen or

• Synthetic materialsArtificial

Natural Casings

Natural casings are mainly derived from small and large

intestines from sheep, goats and pigs, but also from cattle

and horses. They

1. Are strong enough to resist the pressure produced by filling

them with sausage mix

2. Are permeable to water vapour and gases, thus allowing fillings

to dry

3. Absorb smoke for additional flavour and preservation

4. Expand or shrink firmly attached to the sausage mix and

5. Can be closed at the ends by tying or clipping.

Characters:

Variable strength & length

Low cost

Best smoke penetration

Stored in salted condition

Most tender

Breakage during processing

Suspected quality (hole/tear, microbial)

Characteristics of casings Natural Collagen Cellulose

Refrigeration storage Yes Yes No

Degree of tenderness Most tender Less tender Peeled

Break during processing Most likely Less likely Least likely

Cost Low High Low

Soaking & flushing before use Yes No Sometimes

soaking

Ease of smoke penetration Most

penetration

Less

penetration

Least

penetration

Best machinability Least Less Best

Best product yield Least Less Best

Printability None Limited Best

Ease of plant storage Least storage Less storage Best storage

Strength Variable High and

Uniform

Good and

Uniform

Length Variable Standardized Standardized

Microbial quality Suspected Good Good

FACTORS INFLUENCE THE QUALITY

Health of the animal,

Species, age, breed,

Fodder consumed,

Conditions under which the animal was raised,

Portion of the intestinal tract utilized,

And how the product is handled and

Processed after the animal is slaughtered etc.

INTESTINE AS RAW MATERIAL FOR CASINGS

I. Mucose membrane with finger-like outgrowths for enlarged surface area

II. Submucose membrane, firm-elastic layer mainly of connective tissue

III. Muscular layer, the circular internal one, the outside one longitudinal

IV. Serose membrane thin coating covering the abdominal cavity from inside

and surrounding all organs.

IV

III

II

I

Terminology used in Casing Industry

Casings Generally refers to sheep and goat intestine alone

RoundsCasings from small intestine of cattle mainly, but

also from sheep, goat or pig

Runners Casings form small intestine of cattle

MiddlesCasings from large intestine of cattle or sometimes

pig

Weasand Casings from the oesophagus of all species

Bung Casings from the caecum

Maws or

StomachsCasings from cleaned pig stomach

Chitterlings Casings from part of large intestines of pigs.

CASING FROM SHEEP INTESTINE

CASING FROM PIG INTESTINE

CASING FROM CATTLE INTESTINE

Cleanliness: Clean & sound, stain free, devoid of fat, parasite

nodules, ulcer , defects

Strength: Strong enough to withstand pressure during filling,

stuffing & processing

Length: Standardized (sheep & hog-91.4 m, beef round-180 m)

Caliber (thickness): Sheep-14 mm, hog-35 mm, beef-35 mm

Curing: Two types, salted & cleaned, some time it may be dried

Packaging: Mainly wooden and plastic container

FACTORS INFLUENCING THE QUALITY

OF CASING

APPROXIMATE LENGTH OF CASING

FROM ANIMALS

Species TypeLength

In meters In feet

Cattle Runner 25-40 90-135

Middle 5.5-7.5 20-25

Bung 1-1.5 4-4.5

Weasand 5.5 18-20

Bladder20-35 cm

wide

8-15 inches

wide

Sheep Round 27 90

Goat Round 22 75

Storage of casings Sheep and Goat casings are generally stored wet and

salted– called salted sheep casings/salted goat

casings

Cattle casings are generally dried in processing and

sprinkled with insecticide—dried cattle casings

A. For salted sheep / goat casings, 1 hank= 91.4 m

B. For dried cattle casings , 1 Hank= 180m in case

of runner and 90 m in case of middles

1. Casings should be manufactured from gut of healthy

animals

2. Intestines for processing should not have ulcers and

heavy parasitic infestation with nodules.

3. Sanitary handling conditions should be maintained

from slaughter till final packaging.

4. The product should be clean with good colour and

without objectionable odour.

5. It should have proper length and be sufficiently cured

STEPS IN CASING PREPARATIONRemoval

Pulling/running(separation of mesenteric membrane)

Chilling (at 10º C)

Stripping

Flushing

Fatting (removal of fat)

Fermentation (for 1-2 days, at 20ºC)

Turning (turn inside out)

Sliming (removal of mucous lining)

Measuring (in inflated condition)

Inspection & grading (checking of colour, cleanliness, pin hole, cuts

etc.)

Preservation (sheep, goat-in wet salted; cattle-dried)

Packing (tin cans lined with polyethylene)

STEPS IN CASING PREPARATION1. Removing the intestine from the animal- the

intestinal tract should be removed carefully without anydamage or cuts. A ligature is made to check the escapeof contents.

2. Running or Pulling - the intestines are detached fromloose mesentery attachment and fat.

Pulling of sheep intestine

STEPS IN CASING PREPARATION3. Chilling- the green intestines may be chilled at 10oC if the

processing is not possible immediately

4. Stripping - The intestinal contents are stripped from the

intestines either by hand or by machine under a spray of

water, which washes away the contents as they are

expressed.

The water spray also serves to

clean the casing.

Stripping

STEPS IN CASING PREPARATION5. Flushing- tap water can be forced through the gut in

order to flush off the remaining intestinal contents

6. Fatting- all fat adhering to the intestines must be

removed. Scrapping in case of sheep and goat intestines

can do it, whereas in buffalo, it may require tearing,

pulling and even use of knife or Brushes.

Loosening of tissue layers

using a small-scale

manual casing cleaning

machine

STEPS IN CASING PREPARATION

7. Fermentation- the intestines are allowed to ferment

for 1-2 days in winter by immersion in water at 20o C.

This facilitates easy removal of mucous membrane and

slime due to bacterial action. However, in summer little

salt can be added to prevent over fermentation.

8. Turning- buffalo and cattle intestines only arerequired to be turned inside out for efficientsliming.

STEPS IN CASING PREPARATION9. Sliming -It is the removal of tissue layers done with

the help of sliming stick or plastic knife or shells.The process becomes easier if casings are dipped in asliming solution containing 0.2% Sodiumpyrophosphate and 1% sodium chloride for 15-20minutes.

a = unprocessed casing

b1 = processed casing

(slimed and cleaned)

b2 = processed casing

(slimed and cleaned and

being flushed with

water)

c = "slime" removed

from inside of casing

d = tissue layers

removed from outside

STEPS IN CASING PREPARATION10. Measuring- the width and length of the casing are

measured.

11.Inspection and grading- the casings are inspected

for cleanliness, colour, pin holes, cuts, blood spots etc.

12. Preservation- Stored overnight in ice and 15 to

20% saturated salt solution. Cured - rubbing with salt;

allow to set for 1 week.

STEPS IN CASING PREPARATION13. Packing:- Containers such as barrels or boxes

preferably of hard wood should be used with

recommended insecticide for dried cattle casings.

For wet salted sheep casings metal tins, which are

completely lined from inside with food grade

polyethylene are used for storage and transport.

14. Resalting

SALTED SHEEP

CASINGS

Hard wooden box used for

dried cattle casings

Required equipments Plastic/wooden scrapper

Gut cleaning table

Fermentation & chilling tank

Stripper with rubber roller

Bronze crusher

DEFECTS COMMON IN CASING

Dull colour: grayish or greenish instead of white or

milky

Nodules: it may be due to round worm in intestine

Holes & laceration: formed due to negligence or rough

handling

Salt burn: due to long storage in salt or due to loose

packing, leaving air inside

Defective grading

Twisting of gut (kink)

Black spot (due to bacterial purification)

Cicatrices (scar of healed up wound)

ARTIFICIAL CASING

Artificial casings are made of collagen, cellulose, or even plastic and

may not be edible. Artificial casings from animal collagen can be

edible, depending on the origin of the raw material.

Collagen

Cellulose

Plastic casings

CELLULOSE CASINGS

Cellulose casings are usually classified into three types:

1. Small cellulose,

2. large cellulose and

3. Fibrous (paper impregnated with cellulose).

Cellulose casings are prepared from a special grade of cotton lintels,

which are solubilized, and regenerated into casings of any desired like.

A clear cellulose casing is commonly used for sausage, which is not

coloured or which is to be coloured by adding dyes to the water in

the cooker.

Plain cellulose casings are available in a variety of sizes with stretch

and shrink characteristics (similar to those of natural casings).

CELLULOSE CASINGS

COLLAGEN CASING

Collagen casings are mainly produced from the collagen in beef

or pig hides, and the bones and tendons. It can also be derived from

poultry and fish.

The latest generation of collagen casings are usually

more tender than natural casings but do not exhibit the

“snap” or “bite” of natural casing sausages.

The biggest volume of collagen casings are edible, but a

special form of thicker collagen casings usually peeled off

Collagen casings are less expensive to use,

give better weight and size control, and

are easier to run when compared to natural casings.

COLLAGEN CASING

PLASTIC CASINGS

Plastic casings are extruded like most other plastic products

generally made from polymers such as Polyamide, Polypropylene

or Polyethylene

Polyamide (Nylon) plastic casings are the most commonly used in

production of cooked sausages