TREATMENT AND DISPOSAL OF BY-PRODUCTS OF SLAUGHTER

1. TREATMENT AND DISPOSAL OF BY-PRODUCTS OF SLAUGHTER 4TH YEAR LECTURE 4 th year Lecture

2. Main product of slaughter is carcass meat • Definition – everything from abattoir or butcher shop not sold directly as food or not carcass meat Why treat? • Rapid hygienic disposal, • Avoid decomposition • Avoid obnoxious odors • Avoid contamination of fresh meat BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

3. Why process? • Brings economic returns • By- products are divided into edible and inedible • Edible by-products e.g. liver, kidneys, thymus , pancreas, edible blood, fat, tripe • Inedible include bone, hooves, hides and skins • When edible by-products are affected by conditions that make them unfit for human consumption- inedible BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

4. FATS • Sources – trimmings from kidney, intestines, channel and other organs • Edible fat processed into oleo oil and oleo stearin • Inedible fats processed into soap manufacturing, glycerine – medicinal preparations, gun powder, cordite and dynamite. BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

5. Processing of edible fat • low FFA any processing ensures that FFA remains low by initial cold storage of raw material, low processing temperatures and minimized cooking times • Wet rendering – pre-cut raw materials injected with steam to 140oC under pressure for 3-4 hrs • Pressure released and fat drains out purified by gravity or centrifugation- removes water • Greases or proteinaceous solids removed and fat extracted by solvents BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

6. Dry rendering • Similar to wet rendering but initially uses steam and water for 1.5 -2 hrs to drive water out of fat • Continuous low temperature rendering uses heating, separation and cooling in a continuous flow. Material is minced, melting by steam at 90oC,separation of liquid fat from solids by centrifugation, heating, centrifugation and cooling. During rendering care taken to prevent breakdown of fat into FFA and glycerides by lipases active at 40-60oC BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

7. Stomachs and Intestines • Used in pet foods manufacture • Human consumption (tripe) if passed fit. • emptied and washed, fat trimmed off, scalded in water containing soda, scrapped, cooked at 49-60oC. • Rumen contents used for compost, biogas generation • Suckling calves, rennet is extracted from the abomasum BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

8. Blood • When collected hygienically used for human consumption. Uncontaminated with ingesta, urine, or foreign material. Originate from healthy animals • Blood recovered from animals ranges from 3-4% of live weight in cattle and pigs; 4-4.5% in sheep, 3.5-4% in lambs 5-6% in calves. Anticoagulants are used • Used to make black pudding (muturas), or for separation of plasma and red cells. • Red cells for black pudding or blood meals • Plasma blood transfusion services. BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

9. Inedible blood collected without due care. • Dried into blood meal by drying to final water content of 8-10%; coagulation in batches draining, pressing and final drying; preheating, coagulation and separation followed by drying • Bones • Amount depends on whether meat is deboned. • Bones mixed with other condemned material and into meat and bone meals • Products of bone processing are fat, bone meal, gelatine and meat and bone meal. • Due to its high calcium and phosphorous content bone meal used in poultry feeds and fertilizers. BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

10. Calcined bone from roasting in air is used in high class pottery, china, refining of silver and in copper smelting • Bone charcoal is used in sugar refining, case hardening in steel manufacture, removal of fluorine in water (bone powders) • Hoofs and horns • Hoofs are removed by stepping in hot water then drying • White hoofs used in the manufacture of combs, buttons • Stripped and black hoofs are used in hoof meal fertilizer for grape vines • Horns used for manufacture of hairpins, buttons, knife handles,. Pig hairs used in making foam-type fire extinguishers fluids BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

11. Hair and bristles • Cattle hairs go with the hide, separated by the tanners used by plasterers as a binding agent • Used as an insulating material in carpet manufacture after purification with HCl to remove lime. • Long black and tail thistles of pigs – brush making, shaving brushes, stuffing mattresses (pigs) after purification BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

12. Hides and Skins • Represents about 12% of value of the animal, carcass 80% and by-products 7% • Hide is tanned and made into leather (shoes, belts) and sole leather. • Sheep skin into leather for gloves DISPOSAL of condemned materials • sterilization –rendering • Incineration • Deep burial pits BY- PRODUCTS OF SLAUGHTER 4 th year Lecture

13. References • Meat Hygiene –Gracey • Purpose – Understand • Utilization of different by-products of slaughter • Disposal methods of condemned material 4 th year Lecture