A rendering plant is a processing operation where dead animals are recycled into products from human food to biodiesel. The remains and waste from slaughterhouses are the primary contributors to these facilities. Heads, hooves, bones, blood, offal (internal organs) and anything else that cannot be used ends up at a rendering plant.
Carcasses of dead animals from livestock and confinement operations are the secondary contributors. A rendering plant will also take dead horses, llamas and other farm and zoo animals. Remains of dogs and cats, roadkill (deer, skunks, rats and raccoons) end up there as well. Veterinary clinics and animal shelters also rely on rendering plants for their euthanized animals. They also accept throwback or rejected meat from supermarkets.
The majority of edible rendering products are sold to feed manufacturers as a source of protein, calcium and phosphorous. The manufacturers then take this “food enhancer,” add ingredients to eventually sell as domestic pet food and livestock feed.
Animals that are not slaughtered or euthanized often die from some form of cancer, encephalitis or organ failure. The euthanized animals have been given sodium pentobarbital. This barbiturate shows up in dog and cat food as well as livestock feed because the rendering process will not break it down.
Raw materials also end up in the rendering “soup.” Heavy metals (cattle ID tags, surgical pins) flea collars (organophosphate insecticides), fish oil laced with contraband DDT, Styrofoam™ and plastic from rejected supermarket meat packaging are common ingredients.
Final products have also identified antibiotics, hormones and pesticides. Some chemicals, such as sulfa, actually become concentrated during the rendering process. It is an unavoidable concession that toxic waste ends up in rendering plant final products.
The goal of any rendering plant is financial and it is not cost-effective to take the time to separate intestines, eyeballs, feathers, hair, bones or rancid restaurant grease. It is not a requirement to identify animals that have died of natural causes for edible rendering.
The end product will dictate the procedure used at the rendering plant. One process cooks the soup past boiling, and then removes the moisture. It is ground into a powder for bone meal or recycled meat for pets, zoo and farm animals.
Dairy animals, cattle, hogs, poultry, sheep and fish are all consuming the rendering plant products on a daily basis. Most of these animals are natural herbivores but have commercially become carnivores and most often cannibals.
The rendering plant also prepares products considered “edible rendering” for humans. This process involves the chopping of edible materials (primarily fat), cooking at low temperatures, and then separating the liquid and fat from solids through a centrifugal separation.
Due to the fear of bovine spongiform encephalogathy (mad-cow disease, BSE), spinal cords are now forbidden in rendering products for human consumption. Due to the lack of vigilance, however, proper inspections are not performed and these types of items are not separated properly.
Human edible rendering includes meat by-products, chicken fat, beef fat, lard, fish oil, fish meal, bone meal and tallow. Esters, found in ales, also come from rendering. Tallow is used in many foods, flavorings and pharmaceutical products. Non-edible tallow products are wax products, crayons and soaps.
Other end products include all forms of cosmetics, toothpaste, nasal sprays, shampoos, creams and ointments. Plastics, rubber products, solvents and toys are also products that come in close human contact. Anything that includes the ingredients glycerin, linoleic acid, oleic acid, steric acid, tallow, meat or bone meal are rendering plant source products.
Meat packing companies benefit from producing edible rendering as a side business. However, this industry is not well regulated, nor is there any consistency established. You cannot be sure how your fat product was processed, or its source.
With the high volume of meat consumption in the world today, the rendering plant industry is mandatory to resolve the problem of animal remains. Without this recycling from slaughterhouse waste, we would be threatened with uncontrolled viral and bacterial epidemics. Rendering has been a craft carried on for centuries in kitchens and shops to make candles, soap, ghee (clarified butter) and lard. It has become a worldwide, multibillion-US Dollar industry.
As long as animals are consumed, rendering plants are necessary. Most environmentally concerned citizens believe that costly programs and unmanageable regulations get the focus rather than cleaning up the industry to produce safe products.
Bringing awareness of the animal feed quality, the consequential threat they pose to the animals we eventually eat, and the pets we love should be enough to bring social demands for quality regulation in many people's opinion.