Few real life phenomena more closely approximate science fiction horror than the prion responsible for bovine spongiform encephalopathy (BSE), commonly known as "mad cow disease." The story of how BSE...
Few real life phenomena more closely approximate science fiction horror than the prion responsible for bovine spongiform encephalopathy (BSE), commonly known as “mad cow disease.” The story of how BSE got into the human food chain — precipitating a health scare and the slaughter of millions of herd animals (especially in the United Kingdom) — is well known. Less well known is how regulated changes in the handling of animal byproducts devastated the rendering industry by turning formerly profitable materials into expensive hard-to-dispose- of wastes.
BSE creates holes in the brain (hence “spongiform”); “downer” cows begin to stagger and eventually collapse and die. The human variant, Creutzfeldt-Jakob disease (CJD), similarly causes dementia and death, and belongs to a family of transmissible spongiform encephalopathies that affect a wide range of animals. Fear that BSE-infected meat could cause illness in humans led to the precautionary destruction of herds and became a trade issue, with bans established against meat from countries with even a single BSE case.
BSE investigations triggered close scrutiny of the slaughtering, processing and rendering industries where, it turned out, animal byproducts were being turned into feed in a cycle never contemplated by Mother Nature. Ruminants and non-ruminants alike — including household pets — were eating one another’s processed offal, creating an environment in which the BSE prion could flourish.
This is where the science fiction horror comes in. The BSE prion, it turns out, is virtually indestructible. It can survive for many months in such unlikely places as a blood splattered slaughterhouse wall, weathering hot and freezing temperatures, ready to drop back into meat products, to be consumed and again infect an unsuspecting host. The prion can even survive fire, so it turns out that when the authorities burned animal carcasses across Great Britain, they unwittingly spread prions across the lands of grazing animals, for future take up into the food chain.
In July 1997 the Canadian Food Inspection Agency (CFIA) passed a mammalian-to-ruminant feed ban that was enhanced by a stricter ban in July 2007. The 2007 “enhanced feed ban” regulation requires segregation of all specified risk material ( “SRM” — the “crax” composed of brains, eyes, spinal columns, ganglia, large intestine, etc.) through meat processing, rendering and disposal. SRM is no longer allowed in any type of feed, pet food or fertilizer.
The CFIA posts the reports on each case of BSE confirmed in Canada. There have been 15 since May 2003. Interestingly, with each case the government extols that the animal was intercepted before entering the food chain and uses this as proof that our random BSE testing program works. The reality is that every one of these sick animals was a downer cow, so it was not random testing that brought it to attention. For case histories you can visit
The enhanced ban protects animal and human health, but has impacted livestock producers, meat processors and (especially) the rendering industry.
Prior to the EFB taking effect, Canadian renderers had already restructured their operations to process ruminant and non-ruminant meat and byproducts in separate plants. This was not in response to Canadian regulation but rather to a U.S. requirement that all non-ruminant derived proteins be produced in rendering plants certified by the U.S. Department of Agriculture as being free from ruminant products. The segregation of facilities cost the rendering companies a great deal of money; although the government has provided some financial assistance, industry consolidation has occurred. Ironically, the US feed ban — referred to as “feed ban lite” by some in Canada — is not so onerous and doesn’t impose the same segregation, machine and plant cleaning, and disposal restrictions, thereby giving U.S. processors a cost advantage. Regulatory compliance costs and time frames have long been bones of contention in Canada on a number of fronts. These include veterinarian drug approvals, feed variety approvals, plant inspection costs, etc. Small producers have been pushed out, replaced by a few large processors who dominate with their economies of scale.
The bottom line for industry is that the 65,000 tonnes or so of SRM that rendering plants once sold for $150 per tonne as protein have now become an (estimated) $50/tonne liability. Disposal options are few due to the nature of the material (which is unsuitable for a municipal landfi ll), so SRM must be sent to specially approved landfill facilities.
The Canadian Renderers Association is supporting research to determine if SRM might be composted back into a useable product — primarily fertilizer. Given the virtually indestructible nature of the prion responsible for BSE, it will be interesting to see how these tests turn out. The association’s members are being asked to make major investments to run SRM in separate batches (for different end products). This is not easy in continuous feed processes, especially when the CFIA’s segregation rules governing SRM are very strict.
A disposal option under consideration is cement plants, where the high temperature and long residence time would certainly destroy the BSE prion. This alternative is currently used in Europe. However, implementation in Canada has so far been inhibited by cost factors and environmental permitting requirements. This is an area where policy-makers could assist by expediting approval of any environmentally-sound systems that can thoroughly (and affordably) destroy the SRM that must be kept out of the food chain.