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Rendering is an industrial process that converts waste animal tissue into stable, value-added materials. The majority of tissue processed comes from slaughterhouses but also includes restaurant grease and butcher shop trimmings. This material can include the fatty tissue, bones, and offal, as well as entire carcasses of animals condemned at slaughterhouses, and those that have died on farms (deadstock), in transit, etc. The most common animal sources are beef, pork, sheep or poultry. Image File history File links Stop_hand. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... Workers and cattle in a slaughterhouse. ... For other uses, see Fat (disambiguation). ... Scrapple sandwich at the Delaware state fair Offal is the entrails and internal organs of a butchered animal. ... A cut of beef. ... Two halves of a pig being delivered Pork is the meat taken from pigs. ... Species See text. ... Ducks amongst other poultry The Poultry-dealer, after Cesare Vecellio. ...

The rendering process simultaneously dries the material and separates the fat from the bone and protein. A rendering process yields a fat commodity (yellow grease, choice white grease, bleachable fancy tallow, etc.) and a protein meal (meat & bone meal, poultry byproduct meal, etc.). Grays Anatomy illustration of a human femur. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The word commodity is a term with distinct meanings in business and in Marxian political economy. ... Tallow is rendered beef or mutton fat, processed from suet. ... Meat and bone meal (MBM) is a by-product of the rendering industry. ...

Rendering plants often also handle other materials, such as slaughterhouse blood, feathers and hair, but do so using processes otherwise distinct from true rendering. Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... Two feathers Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. ... Young Girl Fixing her Hair, by Sophie Gengembre Anderson Hair is a filamentous outgrowth of dead cells from the skin, found only in mammals. ...

Process variations

The rendering process varies from plant to plant in a number of ways.

1. Whether the end products are to be used as human food is based on the type of raw material and the processing methods.
2. Whether the end products are to be used as animal or pet food
3. The material may be processed wet or dry. In wet processing, water in the form of liquid or steam is added to the material during the rendering process
4. The temperature range used, whether high or low.
5. Processing may be either in discrete batches or in a continuous process.
6. The processing plant may be operated by an independent company that collects the material on the open market, or by the packing plant that produced the material.

Rendering processes for edible products

Edible rendering processes are basically meat processing operations and produce lard or edible tallow for use in food products. Edible rendering is generally carried out in a continuous process at low temperature (less than the boiling point of water). The process usually consists of finely chopping the edible fat materials (generally fat trimmings from meat cuts), heating them with or without added steam, and then carrying out two or more stages of centrifugal separation. The first stage separates the liquid water and fat mixture from the solids. The second stage further separates the fat from the water. The solids may be used in food products, pet foods, etc, depending on the original materials. The separated fat may be used in food products, or if in surplus, it may be diverted to soap making operations. Most edible rendering is done by meat packing or processing companies. A slice of bread spread with lard was a typical staple in traditional rural cuisine of many countries. ...

An alternative process cooks slaughterhouse offal to produce a thick lumpy stew which is then sold to the pet-food industry to be used principally as tinned cat and dog foods. Such plants are notable for the offensive odour that they can produce and are often sited well away from human habitation. Look up CAT, cat, Cat in Wiktionary, the free dictionary. ... Trinomial name Canis lupus familiaris The dog is a mammal in the order Carnivora. ...

Rendering processes for inedible products

Materials that for aesthetic or sanitary reasons are not suitable for human food are the feedstocks for inedible rendering processes. Much of the inedible raw material is rendered using the "dry" method. This may be a batch or a continuous process in which the material is heated in a steam jacketed vessel to drive off the moisture and simultaneously release the fat from the fat cells. The material is first ground, then heated to release the fat and drive off the moisture, percolated to drain off the free fat, and then more fat is pressed out of the solids, which at this stage are called "cracklings" or "dry-rendered tankage". The cracklings are further ground to make meat and bone meal. A variation on a dry process involves finely chopping the material, fluidizing it with hot fat, and then evaporating the mixture in one or more evaporator stages. Some inedible rendering is done using a wet process, which is generally a continuous process similar in some ways to that used for edible materials. The material is heated with added steam and then pressed to remove a water-fat mixture which is then separated into fat, water and fine solids by stages of centrifuging and/or evaporation. The solids from the press are dried and then ground into meat and bone meal. Most independent renderers process only inedible material. bone meal n. ...

History

The development of rendering was primarily responsible for the profitable utilization of meat industry by-products, which in turn allowed the development of a massive industrial-scale meat industry that made food more economical for the consumer. Rendering has been carried out for many centuries, primarily for soap and candle making. The earliest rendering was done in a kettle over an open fire. This type of rendering is still done on farms to make lard (pork fat) for food purposes. With the development of steam boilers, it was possible to jacket the kettle to make a higher grade product and to reduce the danger of fire. A further development came in the nineteenth century with the use of the steam "digester" which was simply a tank used as a pressure cooker in which live steam was injected into the material being rendered. This process was a wet rendering process called "tanking" and was used for both edible and inedible products, although the better grades of edible products were made using the open kettle process. After the material was "tanked", the free fat was run off, the remaining water ("tank water") was run into a separate vat, and the solids were removed and dried by both pressing and steam-drying in a jacketed vessel. The tank water was either run into a sewer or it was evaporated to make glue or protein concentrate to add to fertilizer. The solids were used to make fertilizer. It has been suggested that Soapmaking be merged into this article or section. ... A collection of lit candles on ornate candlesticks A close-up image of a candle showing the wick and the various regions of the flame. ... A kettle is a kitchenware piece. ... Image of a sewer pipe // Function Sewers transport wastewater from buildings to treatment facilities. ... Historically, glue only refers to protein colloids prepared from animal tissues. ... spreading manure, an organic fertilizer Fertilizers (British English, also fertilisers) are compounds given to plants to promote growth; they are usually applied either via the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves. ...

The pressure tank made possible the development of the Chicago meat industry in the USA, with its huge concentration in one geographic area, because it allowed the economic disposal of by products which would otherwise overwhelm the environment in that area. At first, small companies that sprang up near the packers did the rendering. Later the packers themselves took up the industry once they saw the potential. Gustavus Swift, Nelson Morris, and Lucius Darling were among the early pioneers of the U.S. rendering industry with their personal backing and/or direct participation in the developing rendering industry. Nickname: The Windy City, The Second City, Chi Town, The City of Big Shoulders Motto: Urbs In Horto (Latin: City in a Garden), I Will Location in Chicagoland and Illinois Coordinates: Country United States State Illinois County Cook Incorporated March 4, 1837 Mayor Richard M. Daley (D) Area    - City 606. ... Gustavus Franklin Swift (June 24, 1839 – March 29, 1903) founded a meat packing empire in the Midwest during the late nineteenth century, which he presided over until his death. ...

Technological innovations came rapidly as the 20th century advanced. Some of these were in the uses for rendered products and others were in the rendering methods themselves. In the 1920's, a batch dry rendering process was invented, in which the material was cooked in horizontal steam-jacketed cylinders that were similar to the fertilizer dryers of the day. Advantages claimed for the dry process were economy in energy use, a better protein yield, faster processing, and fewer obnoxious odours attending the process. Gradually, over the years, the wet "tanking" process was replaced with the dry process, so that by the end of World War II, most rendering installations used the dry process. In the 1960's, continuous dry processes were introduced, one using a variation of the conventional dry cooker and the other making use of a mincing and evaporation process to dry the material and yield the fat. In the 1980's high energy costs popularized the various "wet" continuous processes. These processes were more energy efficient and allowed the re-use of process vapours to pre-heat or dry the materials during the process. Combatants Major Allied powers: United Kingdom Soviet Union United States Republic of China and others Major Axis powers: Nazi Germany Italy Japan and others Commanders Winston Churchill Joseph Stalin Franklin Roosevelt Harry Truman Chiang Kai-Shek Adolf Hitler Benito Mussolini Hideki Tojo Casualties Military dead: 17,000,000 Civilian dead...

Benefits of rendering

After rendering, the materials are much more resistant to spoiling. The fat can be used in animal feed, in soap-making, in candles, as a raw material for biodiesel production, and as a feed-stock for the chemical industry. The bone and protein becomes dry particles known as meat and bone meal. For many years meat and bone meal were fed to cattle. This practice is now prohibited in developed countries because it is believed to be the main route for the spread of BSE (mad-cow disease). Meat and bone meal is still fed to non-ruminant animals in the United States. Biodiesel refers to a diesel-equivalent, processed fuel derived from biological sources. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... Meat & bone meal Meat and bone meal (MBM) is a by-product of the rendering industry. ... Bovine spongiform encephalopathy (BSE) commonly known as mad cow disease, is a fatal, neurodegenerative disease of cattle, which infects by a mechanism that surprised biologists on its discovery in the late 20th century. ... Families Antilocapridae Bovidae Cervidae Giraffidae Moschidae Tragulidae A ruminant is any hooved animal that digests its food in two steps, first by eating the raw material and regurgitating a semi-digested form known as cud, then eating the cud, a process called ruminating. ...

Tallow, derived from beef waste, is an important raw material in the steel rolling industry providing the required lubrication as the sheet steel is compressed through the rollers Tallow is rendered beef or mutton fat, processed from suet. ... The old Steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon content between 0. ...

In the absence of the rendering industry, the cost of waste disposal of waste animal material would be very high and would place a significant economic and environmental burden on areas involved in industrial scale slaughtering.

Economic impacts

Other major factors which impacted the industry in the 20th century were the popularization of chemical fertilizers, the development of synthetic detergents, the widespread adoption of "boxed beef" in the USA, and the change in consumer eating habits to reject animal fats. In the early 20th century the low cost of synthesis of artificial nitrogen fertilizers undermined the economic use of animal waste to enrich soils. This resulted in the loss of a substantial market for meat by-product solids. But this lost market was replaced by the realisation that these products made good feed for animals. After World War II synthetic detergents came on the scene which eventually displaced soaps for both domestic and industrial washing uses. Thus, in the early 1950's over 50% of the inedible fat market disappeared. Diversion in these materials into animal feeds soon replaced the lost soap market and eventually became the single largest use for inedible fats.

The widespread use of "boxed beef" in which the beef was cut up into consumer portions at the packing plant rather than at the retail level in local butcher shops and markets meant that the fat and meat scrap raw materials for renderers stayed at the packing plants and were rendered there by packer renderers, rather than by the "independent" renderering companies.

The rejection of animal fats by diet-conscious consumers led to a surplus of edible fats and their resultant diversion into soapmaking and oleochemicals, displacing inedible fats and contributing to the market volatility of this commodity. Oleochemicals are chemicals derived from biological oils or fats. ...

The rendering industry is one of the oldest recycling industries, and made possible the development of a large food industry. The industry takes what would otherwise be waste materials and makes useful products such as fuels, soaps, rubber, plastics, etc. At the same time, rendering solves what would otherwise be a major disposal problem. As an example, the USA recycles more than 21 million metric tons annually of highly perishable and noxious organic matter. In 2004, the U.S. industry produced over 8 million metric tons of products, of which 1.6 million metric tons were exported.

Reference

1. National Renderer's Association, Render Magazine, April 2005.
2. National Renderer's Association, North American Rendering-The Source of Essential High Quality Products. Burnham, Frank
3. Rendering, The Invisible Industry, Aero Publishers, 1978.Clemen, Rudolph
4. By Products in the Packing Industry, University of Chicago Press, 1927

Franco, Don and Swanson, Winfield, The Original Recyclers, APPI, FPRF and NRA, 1996

See also kitchen rendering. In the kitchen, rendering can mean clarifying butter into ghee, suet into tallow and bacon fat into lard. ...

External links

Rendering companies

• Griffin Industries, Inc.
• Darling International
• Baker Commodities
• PDM Group

Industry organizations

• Australian Renderers' Association Inc.
• National Renderer’s Association (US)
• Fats and Proteins Research Foundation (US)
• Animal Protein Producers Industry (US)
• United Kingdom Renderers' Association (UK)

Industry publication

• Render magazine