Chapter 6: Perform pig slaughter

Pig slaughter is a critical process in pig production that directly affects meat quality, food safety, and economic returns. In Kenya, where pig farming is expanding to meet growing demand for pork, proper slaughter techniques and the use of appropriate tools and equipment are essential for both ethical and commercial reasons. Understanding the specifications and correct handling of slaughter tools ensures compliance with health standards and enhances efficiency in abattoirs and on-farm slaughter settings. This chapter focuses on the tools, equipment, and materials necessary for efficient and hygienic pig slaughter.

6.1 Slaughter tools, equipment and materials

Pig slaughter is done with a set of tools and equipment that restrain and stun the pig, bleed it, remove its hair, hang the carcass and cut it up. The materials used with them keep the work clean. Each item must be fit for the job, kept sharp or in working order and easy to clean, because dirty or blunt equipment spoils meat, causes injuries and makes the killing of the pig less humane. This topic names the main tools, equipment and materials used in a pig slaughterhouse or slab: knives, stunners, scalding tanks, gambrel and hoists, and cutting boards and tables. Preparing the slaughter house and the handling of the pig are covered in Preparation of slaughter house/slab and Pre-slaughter handling of pigs.

Knives

Knives are the main hand tools of slaughter. A different knife is used for each task, and all must be kept sharp and clean.

• Handles and blades: Stainless steel blades with plastic handles are easy to clean and do not rust, and a handle should be non-slip.
• Sharpening: A sharp knife cuts cleanly, needs less force and slips less often than a dull one, so it is steeled often and sharpened on a stone when it is blunt.
• Sterilising: Knives are washed and then placed in hot water at 82 degrees Celsius or more between uses, or in a disinfectant approved for food contact. Two knives are used in turn, so that one is always sterile.
• Safety: Carry knives in a sheath or belt holder, cut away from the body, and wear a cut-resistant glove on the hand that holds the meat.
• Saw and cleaver: A carcass saw or heavy cleaver is used to split the carcass along the backbone.

Stunners

A stunner makes the pig unconscious before it is bled, so that it feels no pain. Stunning must be done correctly, as quickly as possible and by a trained person. Bleeding follows within seconds.

• Electrical stunner: Tongs with two electrodes are placed on either side of the head, so that an electric current passes through the brain. It is widely used on pig slaughter lines because it needs no bullet and gives a quick, reliable result when the electrodes are placed properly. The tongs are kept clean and dry, the electrodes wetted for good contact and the operator wears rubber gloves and boots.
• Captive bolt pistol: A cartridge or compressed air drives a bolt into the skull, causing concussion. It is used on a restrained pig, with the bolt aimed at the middle of the forehead, slightly above the eyes.
• Gas stunning: Large plants use carbon dioxide in a chamber. It needs expensive equipment.
• Restraining equipment: A narrow race or a V-shaped restrainer holds the pig still for stunning.
• Checking that the pig is stunned: The pig collapses and its body is limp, it does not breathe regularly and there is no response when the eye is touched. A pig that shows signs of recovery is stunned again at once.

Scalding tanks

A scalding tank holds hot water in which the carcass is dipped after bleeding, so that the hair loosens and can be scraped off. Pigs are scalded and scraped, rather than skinned, in many slaughter units.

• Tank: A trough long enough for a whole pig and about the depth of the carcass, made of stainless steel, galvanised steel or lined masonry, with a drain, a lid or cover and a way of heating the water.
• Water temperature: About 60 to 65 degrees Celsius, checked with a thermometer. Water that is too hot sets the hair on the skin and cooks the skin, and water that is too cool does not loosen the hair.
• Time: The carcass is moved in the water for a few minutes, tested by pulling a little hair. It is removed as soon as the hair comes away easily.
• Scrapers: Bell scrapers and knives, to remove the hair after scalding, and a dehairing machine in larger units.
• Hygiene: Clean the tank after use and change the water often, since hot water holds blood, dirt and microorganisms that spoil meat.
• Safety: Hot water and steam burn, so cover the tank, keep the floor non-slip and lift the carcass with a hoist and not by hand.

Gambrel and hoists

A gambrel is a strong metal bar or spreader with two hooks, which is passed behind the hind leg tendons at the hock to hang the carcass head-down. A hoist is a lifting device that raises the pig for bleeding and moves the carcass between the stages of dressing.

• Gambrel: Made of stainless steel or heavy galvanised steel, with a wide enough spread to hold the legs apart and a loop at the top for the hoist hook or rail trolley.
• Hoist: A chain hoist, a block and tackle, or an electric hoist fixed to a beam or an overhead rail, rated for more than the heaviest pig to be lifted.
• Overhead rail and trolleys: A rail with trolleys carries the hanging carcass from bleeding to scalding, dressing and the chiller without lifting it by hand.
• Bleeding rail: The carcass hangs from the rail while the blood drains, so that the carcass does not touch the floor and bleeds fully.
• Safety: Check chains, hooks and welds before use, never stand beneath a raised load, and do not exceed the rated load of the hoist.

Cutting boards and tables

Cutting boards and tables are the work surfaces for cutting up the carcass.

• Dressing table: A table made of stainless steel or tiled masonry with a smooth, non-absorbent surface, a raised edge and a slight slope towards a drain. Its height is comfortable for the person working at it.
• Cutting boards: Boards of food-grade plastic are used for cutting meat and are replaced when deeply scored. Wooden boards are avoided because blood and fat sink into cracks and are hard to clean. A red board is used for raw meat.
• Care: Scrape and wash tables and boards after use with detergent and hot water, rinse and disinfect, and let them dry.
• Separation: Edible meat, offal and condemned parts are placed on separate tables or in separate containers, so that they are not mixed.

Cleaning and protective materials

• Detergents and disinfectants: Detergent removes fat and blood, and an approved chlorine-based or iodine disinfectant is applied afterwards at the dilution on the label.
• Hot and cold water: A hose with clean water of drinking quality is used to wash carcasses and surfaces, with hot water for knives and equipment.
• Containers: Clean containers collect blood, and leak-proof bins with lids and clear labels hold offal, waste and condemned materials.
• Protective clothing: Workers wear clean overalls, rubber boots, waterproof aprons, hair covers and gloves. Disposable gloves are used once and thrown away.
• First aid and hand washing: A first aid kit is kept at hand for cuts, and clean water and soap for washing the hands.

Green first aid kits with cross symbols (Source: Wikipedia (First aid kit))

Chapter Summary

This chapter covers the essential tools, equipment, and materials required for pig slaughter, emphasizing their specifications and uses. It then details the preparation of the slaughterhouse or slab to ensure a clean and organized workspace. Proper pre-slaughter handling of pigs is discussed to minimize stress and promote humane treatment. The humane slaughter process is explained with attention to animal welfare standards. Following slaughter, the chapter outlines carcass dressing techniques and the cleaning of offal to maintain quality. It addresses the preservation methods for dressed meat and the correct procedures for transporting the meat to prevent contamination. Food safety and hygiene measures are highlighted throughout the slaughter process, alongside the handling of by-products and the disposal of condemned materials such as organs and wastes. Finally, the chapter emphasizes the importance of cleaning the slaughterhouse and equipment, maintaining slaughter structures, and keeping accurate records to ensure efficient and compliant operations.