The Middle Ages Butchers’ fat trimmings are used in soaps and candles, the first significant use of rendered animal products.
19th Century The industrial revolution transforms agricultureand the storage of meat. Cattle production increasesand with it comes a burgeoning disposal problem. Rendering–converting animal byproducts into animal feed and other commodities–becomes the solution.
Early 20th Century Fat and water are drained in rendering process and the remaining protein product, called tankage, is used as fertilizer.
1912 A Chicago company adds blood meal to tankage and uses it as a food ingredient for hogs. The hogs win first prize at the International Livestock Show in Chicago in 1914.
WWI and II English farmers feed their cattle cheap, high-protein sources derived largely from slaughterhouse waste, while demand is high in the US for rendered glycerine, used in the manufacture of nitroglycerine explosives.
After the war, with increasingly intensive farming, protein supplements offer accelerated growth of young calves that is too good to resist, and later become a common practice for feeding livestock and poultry.
1947 Chickens’ growth is accelerated by feed mixed with meat and bone meal derived from fish, cattle and other chickens.
1950s Offal from the concentrated poultry industry in the Southeast is collected and processed, introducing new products including poultry byproduct meal and feather meal.
The use of fat from animals in soaps disappears with the advent of petroleum-based synthetic soaps.
1960s and 1970s Rendering industry launches research and development for new end uses for their products. Fats begin to be used extensively as cattle feed, and rendered products find a market in the pet food industry.
Competitive market pressures drive the livestock industry to maximize “efficiency”–cutting costs while increasing growth rates and yields. Innovations in genetics and artificial insemination create super-producing breeds of cows, pigs and chickens. Synthetic hormones and antibiotics also help maximize growth and production levels, while drugs help fend off diseases that might hinder production in growth-stressed animal populations.
To increase production levels of meat and milk, cattle are moved from grazing outside to feeding indoors, where they are force-fed optimum levels of carefully formulated rations–the introduction of the “feedlot.“
1970s At this point, cattle are consuming rendered fats, but their proteins are from grains and soybeans–viewed as costly and wasteful. A search for alternative substances leads to such ingredients in animal feed as: sewage sludge, treated manure, agricultural wastes, retail food wastes, slaughterhouse and tannery wastes, industrial wastes such as sawdust, wood chips, twigs and even ground-up newspapers and cardboard boxes, cement dust from kilns, sludge from municipal composting plants, water from electric generating plants that used fluidized combustion of coal, and waste water from nuclear power stations, the “Four Ds”–dead, dying, disabled, and diseased animals, moisture-damaged or maggot-infested grains, foods contaminated by rodents, roaches, or bird excreta.
The rendering industry admits at one point that rendered feeds carry detectable levels of salmonella and other disease organisms, but insists the amounts fed are too small to cause a problem.
1986 Cattle in Britain begin to suffer from a condition similar to scrapie in sheep, referred to as “mad cow disease,“ due to the behavior of the sick cows. (Scientific name: Bovine spongiform encephalopathy, or BSE). Cause is unknown, though some suspect the feeding of rendered scrapie-infected sheep to cattle.
Early 1990s In Britain, house cats begin dying from beef byproducts in their pet food, while zoo animals are dying from their own feed as well.
1993 Britain has more than 120,000 cattle infected with BSE.
Mid-1990s Britain bans the feeding of meat and bone meal to animals and its use as farm fertilizer.
1997 The U.S. Food and Drug Administration (FDA) bans protein made from cows, sheep, deer, and other so-called ruminants in feed for other ruminants.
It is still legal to feed the rendered protein to non-ruminants, such as pigs and chickens; those animals in turn can be rendered and fed to cows or sheep. Cattle are still being fed composted wastes from chicken coops, including feathers, spilled feed, even feces. Calves are fed beef blood and beef fat.
May 2003 A bull in Canada tests positive for BSE, the first confirmed case in North America.
December 23, 2003 A cow in Washington State tests positive for BSE.
January 26, 2004 FDA bans feeding cow blood, chicken waste, and restaurant scraps to cattle. Over 180,000 cattle in Britain have been infected.
From the non-profit Center for Food Safety. Timeline compiled from information in Mad Cow USA, Rampton and Stauber, 1997, except information after 1997, which was compiled from various news sources.