By-Products of Slaughterhouse | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

5.3. BY-PRODUCTS

• 5.3.1. Slaughterhouse by-products and their utilization

  • By-products of slaughterhouses refer to the residual materials left after the main meat products like beef, mutton, or pork have been harvested.
  • These by-products undergo necessary treatment before being put up for sale.
  • The treatment process is essential not just for economic reasons but also to ensure proper disposal to avoid decomposition, unpleasant odors, and contamination of fresh meat.
  • Efficient processing of slaughterhouse by-products ensures that materials that would otherwise go to waste can be economically utilized.
  • This process is not just a financial consideration but also a social responsibility to safeguard public health interests.

Example: An example of a slaughterhouse by-product is animal bones, which can be processed into bone meal for agricultural use.

Edible and Inedible By-Products in Meat Processing

Overview

• Products apart from the main carcass, such as organs, hides, and skin, are categorized into edible and inedible by-products in meat processing.
• Efficient management of by-products is crucial for maximizing the yield of edible products, especially in larger meat plants, leading to better overall economic efficiency.

Edible By-Products

• Examples of edible by-products include liver, kidney, thymus, pancreas, edible blood, and fat.
• Proper handling of these by-products is essential to ensure high-quality edible products, which are valuable in various industries, notably in the food sector.
• Remnant parts like carcass meat, liver, lungs of cattle and sheep, fat trimmings, udder, spleens, poultry carcasses, heads, necks, bones of sheep, pig's feet, cattle paunches, and blood are commonly utilized.
• Blood, when collected hygienically, has various uses, including direct human consumption.

Handling and Processing

• After chilling, by-products undergo cleaning, trimming, and final freezing before being sent to pet food manufacturers.

Examples of Edible and Inedible Products

• Edible: Raw fat, blood
• Inedible: Stomach and intestinal contents, hide

Summary: By-product Treatment

Key Concepts:

• Fat, stomach, intestines, blood, bone, hooves, horns, hairs, bristles, hides, skins, and glands are by-products that require processing.
• Steer and lamb breakdown percentages for inedible products are provided.
• Pigs have a higher percentage of edible fat compared to other animals.

Processing of Fat:

• Fat is obtained from various parts of animals and has different qualities.
• Rendering methods include wet rendering, dry rendering, and continuous low-temperature rendering.
• Efficient rendering processes maintain low Free Fatty Acid (FFA) values.

Rendering Methods:

• Wet Rendering: Involves pressure batch cookers and steam injection for fat extraction.
• Dry Rendering: Uses heat to evaporate water from fat.
• Continuous Low-Temperature Rendering: A modern, continuous flow method for fat extraction.

Stomach and Intestines:

• Utilization of stomachs and intestines in the pet-food industry.
• Various parts of the stomach are processed differently for specific products.
• Cleaning and processing methods for animal intestines are outlined.

Blood Utilization:

• Hygienic collection and utilization of blood for human consumption.
• Importance of obtaining blood from healthy animals and avoiding contamination.

Available Blood Volumes in Animals

• Species
• Cattle: 75 ml/kg
• Calves: 60 ml/kg
• Pigs: 60%
• Sheep: 65%
• Lamb: 70%

Total Blood Volume

• Species
• Horse: 3-4 ml/kg
• Ox: 5-6 ml/kg
• Sheep: 3-4 ml/kg
• Pig: 4-4.5 ml/kg
• Goat: 3.5-4 ml/kg
• Rabbit: 25 ml/kg
• Chicken: 30-35 ml/kg

Edible Blood Processing

• Small quantities of bovine blood are collected for making black sausages or blood puddings.
• Whole blood is separated into plasma (60-70%) and red blood cells (20-30%).
• Plasma contains 7-8% protein and 91% water, while red blood cells contain 34-38% protein and 62% water.
• Red blood cells can be used for making black sausages or dried into meal.

Inedible Blood Processing

• Inedible blood is often contaminated and has high water content.
• After straining foreign matter, it undergoes drying into blood meal to remove water.
• Drying processes include one-stage drying, coagulation in batches, pressing, and continuous preheating, coagulation, and drying.

Bones Processing

• There are two types of bones: "edible" and inedible. The classification depends on their source and handling.
• 'Edible' bones need to be handled quickly and hygienically.
• With the rise of boneless meat production, there is an increase in edible bones available.
• End products of bone processing include fat, bone meal, and gelatine.
• Bone meal is used in poultry feeds, as a fertilizer, and in various industries like pottery and metal refining.
• Gelatine, derived from edible bones, is used in food production, photography, and other applications.
• In bone meal preparation, attention is paid to maintaining sterile conditions during processing.

Uses of Bone Products:

• Bone meal: Poultry feed and fertilizer component.
• Calcined bone: Utilized in pottery, refining of metals, and manufacturing steel.
• Bone charcoal: Used in bleaching, sugar refining, and steel production.
• Special bone powders: Employed for fluorine removal from water.

Production of Gelatine:

• Gelatine is produced from edible bones post-fat extraction and is used in food, medicine, photography, and more.
• Gelatine sources include veal, beef, and pig's skin.

Hoofs and Horns Processing

• Hoofs are removed by hot water treatment and drying, with white hoofs used in manufacturing horn articles.
• Striped and black hoofs are processed into hoof meal fertilizer.
• Horns are extracted, graded, and utilized in various products like combs, buttons, and fertilizers.
• Hoof and horn meal, along with pig hair, find use in fire-extinguishing fluids.

Uses of Hoof and Horn Products:

• White hoofs: Manufacture of horn articles.
• Hoof meal fertilizer: Fertilizer for grapevines.
• Horn products: Combs, hairpins, ornaments, and fertilizers.

Neat's-foot Oil Processing

• Neat's-foot oil is obtained from cattle feet through a process involving washing, scalding, boiling, and splitting the feet.
• The prolonged cooking and settling of the feet result in a supernatant oil that is then skimmed off and filtered.
• This oil, known for being odorless, serves as a lubricant for delicate machinery and is primarily used in leather manufacturing.

Hair and Bristles Processing

• Cattle hair, along with the hide, is taken to tanners where it is separated from the skin using lime or other chemicals.
• Crude hair is utilized by plasterers as a binding agent, while for other purposes, it undergoes purification through treatment with hydrochloric acid to eliminate impurities.
• After drying, cattle hair possesses excellent insulating properties and is commonly used as felt for placing beneath carpets.
• The long back and tail bristles of pigs are employed in brush-making, with the stiffest bristles obtained during the scraping-off process of a carcass.
• Wild pigs yield the stiffest bristles, historically supplied by Russia and presently also by Canada.
• Previously, shaving brushes were crafted from Siberian and Chinese horse hair, but now they are predominantly made from pig bristles.
• The short hair of pigs, after chemical purification, is used for stuffing mattresses.

Hides and Skins

• Fresh animal hides, like ox hides, contain a significant amount of water, usually around 65%.
• The tanning process for hides involves various steps such as soaking in water, treatment with milk of lime, hair removal, and tanning using different processes like vegetable tanning or chrome tanning.
• Leather derived from hides of bullocks and heifers is commonly used for products like belts and sole leather.
• Sheep skins are utilized for making gloves, with lamb skins used for kid gloves and a process called 'Shammoying' employed for chamois leather gloves.
• Goat skins or hides are also used to create leather known for its durability and attractive surface.

Treatment of Condemned Meat and Offals

• Stringent measures are in place to ensure that only safe and wholesome meat is made available for public consumption.
• Meat inspection laws in various countries classify meat into categories based on its condition, with necessary treatments before sale for meat in less than optimal conditions.
• Systems like the Freibank System in Germany allow for the sale of lower-quality meat at reduced prices under strict supervision to provide affordable protein sources for the community.

By-Products of the Meat Industry

Raw By-Products

• Raw by-products include items like edible and inedible blood, fat, mixed condemned carcasses, and bones classified as edible or inedible.
• These raw materials can be further processed for various purposes, such as making adhesives, pet food, fertilizers, and more.

Processed By-Products

• Processed by-products like plasma, red cells, blood meal, and meat and bone meal are utilized for producing items like adhesives, livestock and poultry feed, gelatine, and more.
• These products have a range of applications, including in food production, industrial uses, and even in medicinal preparations.

Raw By-products

• Horns and hooves
• Stomach (cattle)
• Rumen
• Reticulum
• Omasum
• Abomasum
• Stomach contents after maceration
• Stomach (sheep; Rumen, Reticulum, Omasum, Abomasum)
• Stomach (pig)
• Hide (cattle)
• Hide (sheep)
• Hide (pig)
• Colon, Caecum, rectum (pig)

Processed By-products

• Extracted protein meal
• Brilliant Tutorials
• Horns, hooves
• Edible tripe (Rendered)
• Edible tripe
• Prewashed hide
• Hair
• Trimming (inedible)
• Large intestines (cattle, sheep; Rendered)
• Pelt
• Wool
• Tanned skin
• Gelatine
• Edible Rendered Foam fire-extinguishers, mixed with livestock feed
• Fertilisers
• Buttons, handles etc.
• Edible use, pet food, meat meal
• Pet food, meat meal
• Pet food, meat meal, rennet (from suckling calves)
• Can be used for composting. Stomach contents for cattle feed after proper treatment
• Pet food, meat meal
• Processing and manufacturing pet food, pepsin, haggis casings, chitterlings Leather goods. Collagen casings felt, upholstery
• Fertilisers Wool skin, rugs, clothing chamois leathers Textiles, upholstery Leather goods Jellied food products Meat meal Chitterlings Meat meal

Raw By-products/Processed By-products

• Small intestine (cattle)
• Small intestine (sheep)
• Small intestine (pig)
• Oesophagus
• Trachea
• Mammary gland (cattle)
• Mammary gland (pig)
• Cheek, and head trimmings (cattle and pigs)
• Lungs
• Tongue
• Brain
• Heart
• Liver
• Diaphragm (cattle)
• Spleen
• Tail
• Kidney (cattle)
• Kidney (sheep)
• Kidney (pig)
• Bladder
• Gall
• Gall stones

Processed By-products

• Rendered
• Casings, surgical sutures
• Meat meal, casings, surgical sutures, tennis racket strings
• Meat meal
• Casings, heparin
• Casings, meat meal
• Meat meal
• Meat meal, pet food, pharmaceuticals
• Meat meal
• Meat meal
• Meat products, sausages
• Pet food, heparin
• As tongue, processing
• Edible
• Edible, pharmaceuticals
• Edible, processing
• As spleen, pet food, processing
• As tail
• As kidney, processing
• As kidney
• As kidney
• Meat meal, tallow (not pig)
• Cleaning agent in leather manufacture, paints, dyes, pharmaceuticals
• Pharmaceuticals

Objective: Understanding Organ By-Products in Food and Pharmaceuticals

Raw and Processed By-Products

• Raw by-products include spinal cord (from cattle), genital organs, pancreas (from cattle and pigs), pituitary, thymus, and thyroid (from cattle).
• Processed by-products encompass items like meat meal, ment meal, and pharmaceuticals such as insulin.

Pharmaceutical Use of Organ Products

• Organ products serve a dual purpose in food and pharmaceutical industries.

Social and Economic Implications

• There exists a social obligation to responsibly handle slaughterhouse by-products for public health and hygiene.
• Utilization of by-products like bones for poultry feed or fertilizers, and hoofs/horns for manufacturing, contribute significantly to the economy.

Medicinal Significance

• Endocrine glands like adrenal, pancreas, thyroid, and pituitary are essential for producing hormones vital in human medicine.
• For instance, insulin from the pancreas, thyroxine from the thyroid, and various hormones from the pituitary gland have medicinal value.

Specific Gland Functions

• Adrenal glands produce adrenaline and noradrenaline, crucial steroids.
• Thyroid gland provides thyroxine for thyroid deficiencies.
• Pituitary gland produces growth hormone, oxytocin, and antidiuretic hormone.
• Other organs like testes, pineal gland, and kidney also produce essential hormones and factors.

Overall Utilization

• Various organs serve both as food sources and as valuable components in pharmaceutical production.