Primary processing
The agents involved in the slaughter and primary processing of carcases include:
		1. 2. 3. 4.	Abattoirs (first stage primary processing) - the slaughter and dressing of stock carried out in licensed plants permitted to cut the carcase into quarters. Cutting plants (second stage primary processing) - further cutting into primals (requires a separate cutting licence). This increasingly refers to the production of deboned primal joints, usually accompanied by the vacuum packing, boxing and palletisation of the product. This can include production of consumer portions and diced and minced meat often retail packed ready for shop display. Minced meat and meat preparation plants (third stage primary processing) - breaking down primals into mince and special products such as quick grill steaks. Cold stores Abattoirs, cutting plants (other than those cutting plants only supplying final consumers or caterers) and cold stores have to be licensed by the Food Standards Agency (FSA). Day-to-day control is the responsibility of the Meat Hygiene Service (MHS). The small cutting and meat preparation facilities supplying final consumers or caterers are currently controlled at a local level by Local Authority Environmental Health Officers (EHOs).
Abattoir Size and Ownership
MLC defines five size ranges of abattoirs using the EU definition of livestock units (ELU): 1 cattle beast = 2 calves = 5 pigs = 10 sheep
Abattoirs operating in Great Britain in 2005
Size Very large - over 100,000 ELU Large - 30,000 to 100,000 ELU Medium - 5,000 to 30,000 ELU Small- 1,000 to 5,000 ELU Very Small - under 1,000 Total				% total kill 22.7 54.1 20.5 1.9 0.7 100.0	Number of plants 9 51 81 45 101 287
On a species basis the top 10 largest plants accounted for the slaughtering of 38% of cattle, 45% of sheep and 64% of pigs. Some of the larger companies will own and operate more than one abattoir or cutting plant and often other further processing subsidiaries.
The density and pattern of livestock farming has an influence on the location and structure of the primary processing industry in that it is not the only factor as livestock can be transported large distances from farm to slaughter. Animals are sourced to meet customer specifications.
Most of the medium and small sized abattoirs are multi-species facilities, operated by independent companies. Some will undertake ‘service’ slaughter for others (e.g. they will slaughter animals on behalf of farmers involved in direct sales to consumers, for traditional butchers and also for other slaughterers).
Slaughter plant operations
On arrival at an abattoir animals are rested in a lairage, where ante-mortem inspection is carried out by MHS veterinary officials working on behalf of FSA. If the animals are assessed as fit for human consumption and are clean and dry, they can be slaughtered. MHS veterinary officials also inspect all carcases and their related parts (e.g. heads and internal organs) post-mortem. The slaughtering process involves:
		1. 2. 3. 4. 5. 6. 7. 8.	Pre slaughter handling – at the point of slaughter animals should be unloaded from delivery vehicles as soon as possible, handled in a calm and quiet manner, bedded on clean straw, have access to water and must be fed if held more than 12 hours. Stunning – animals are made insensitive to pain by humane stunning methods. There are three common methods employed, using either captive bolt pistols, electricity or for some pigs CO2 gas. There are also separate specific procedures where religious slaughter principles, such as Halal and Shechita, are involved. Sticking – immediately after stunning, animals are suspended by their hind legs and at least one of the carotid arteries are severed, thus terminating blood supply to the brain; blood is then allowed to drain from the animal (called bleeding or exsanguination). Only fully trained licensed slaughtermen are allowed to kill animals. Dressing – the removal of the head, feet and hide/skin, followed by the removal of the internal organs (called evisceration). Carcases are then split into sides or quarters – three cuts maximum. Weighing and classification – (see section on Carcase Classification) Health marking – fresh meat for sale for human consumption produced in licensed slaughterhouses must be stamped, with the MHS official health mark. This is an internationally recognised symbol indicating that the meat bearing the stamp has been: produced under veterinary supervision; complies fully with all relevant legislation; inspected and passed fit for human consumption. Chilling and storage – is the reduction in temperature of a carcase, to restrict the growth of pathogens and spoilage mico-organisms in meat and to prevent deterioration. The chilling process generally involves placing carcases in chilled conditions of 0°C to 5°C within one hour of slaughter and holding them until an internal muscle temperature of less than 7°C is obtained. Ageing and hanging – is the holding of carcases or primal joints at refrigerated temperatures (0 to 4°C) to improve the eating quality.
The slaughter process involves a considerable weight loss between the weight of the live animal and the end weight of the carcase; this is referred to as the carcase yield, dressing or killing out percentage. As a percentage of the liveweight the killing out percentage for cattle is around 56%, for sheep 50% and for pigs 75% (as more of the animal is consumed), but these can differ depending on the breed, age, weight and classification of the animal as well as the weight of gut fill at slaughter. Carcase classification. Carcase yield calculator.
Cutting plant operations
The size and activity of each cutting plant varies markedly around the industry. Most of the larger abattoirs will also have large cutting facilities. Cutting plants can either be co-located with an abattoir or be on a stand-alone site. Their role is to breakdown/debone carcases into primal joints or cuts; these are then passed on or sold to other agents in the supply chain for further processing. Some are also involved in breaking down primals into even smaller cuts of meat, such as prepared and diced product, and minced in fresh or frozen free-flow form.
Boning and cutting should be carried out in an air-conditioned room to maintain the product temperature at below 7°C. (In smaller plants the product temperature can be maintained by limiting the time the product is out of the chill room).
There are two main types of butchery in the UK:
			Traditional – the carcase is cut following the bone structure thus in some primals and joints with mixed muscles often with different characteristics, this can result in a variety of eating qualities and textures in one joint. Seam – typically a Continental practice now being more widely used in the UK, where the carcase is cut according to muscle position and natural seams between muscles.
For more information: Services, publications and websites British Meat Processors Association: Manufacturing standard for certification British Retail Consortium: Global standard – consumer products British Retail Consortium: Global standard – food Clean livestock Guidelines Meat and Meat hygiene Guidelines Blueprint for Quality Beef Leaflet Blueprint for Quality Pork Leaflet Blueprint for tender lamb leaflet Your Health and Animals - A guide for those working in the meat industry Humane Slaughter Association