Jul 24, 2003 (CIDRAP News) – In the first regulatory change triggered by Canada's recent case of mad cow disease, the Canadian government announced last week that certain high-risk parts of cattle, including the brain and spinal cord, will have to be removed from carcasses at the time of slaughter.
Health Canada announced the plan to require the removal of the brain, spinal cord, and terminal ileum (part of the small intestine) from cattle older than 30 months. These are considered "specified risk materials" (SRM)—tissues that, in an animal infected with bovine spongiform encephalopathy (BSE), or mad cow disease, are likely to carry the infective prion protein. In cattle younger than 30 months, these tissues do not carry the infective agent, according to Health Canada.
The new requirement addresses the chief recommendation made in June by an international team of four veterinary experts who reviewed Canada's response to the BSE case. The team called the removal of SRM from human food and animal feed "the most critical and central measure for public health protection and food safety."
In Canada's Jul 18 announcement, Agriculture and Agri-Food Minister Lyle Vanclief said, "We are taking steps to implement this important measure as soon as possible. By removing SRM at slaughter we are making a very safe system even safer."
However, the Health Canada announcement left some questions unanswered. It did not make clear whether SRM will be banned from animal feed or only from human food. Also, officials did not specify whether all SRM will have to be removed, or just the brain, spinal cord, and terminal ileum. Other high-risk tissues include the tonsils, eyes, and certain nerve bundles.
A Health Canada official told CIDRAP News that the initial regulatory change is aimed at removing SRM from the human food supply. "The announcement made focused on removal of those tissues from the food supply," said Paul Mayers, associate director-general in Health Canada's Food Directorate in Ottawa. "Ministers recognize that the issue around animal feeds continues to be an area under discussion, so there has been no significant decision on the animal feed element."
Mayers said the SRM subject to removal will be detailed in forthcoming regulations, "so what particular tissues will be included in that will be part of that process." In the Jul 18 announcement, Health Canada said its aim was to implement the new policy starting today (Jul 24), but Mayers couldn't say when the regulations would be published.
Eating meat from BSE-infected cattle is believed to be the cause of variant Creutzfeldt-Jakob disease (vCJD) in humans. More than 100 cases of the fatal neurologic disease occurred in Britain and other European countries in the 1990s, following a major outbreak of BSE in British cattle in the 1980s. BSE was believed to have spread in cattle because they were fed meat-and-bone meal containing protein from other BSE-infected cattle. Since 1997 both Canada and the United States have banned the use of meat-and-bone meal from ruminant animals (cattle, sheep, goats, and other cud-chewing animals) in feed for other ruminants.
The BSE case in Canada was reported May 20 after testing of tissue from a cow that had been slaughtered in Alberta in January. The subsequent investigation, including testing of more than 2,000 other cattle, turned up no other BSE cases but did not answer the question how the cow contracted BSE. However, health authorities suspect the cow, which was about 6 years old, might have eaten contaminated feed before the 1997 ban on feeding cattle protein to cattle took effect.
The United States, along with many other countries, has banned the importing of Canadian cattle and beef since the BSE case was revealed. When Canada announced the SRM ban at the end of last week, US Agriculture Secretary Ann Venemann made a brief statement praising the move, but US officials have announced no plans to lift the import ban.
Currently in Canada, the spinal cord is usually removed for quality-control reasons from cattle carcasses intended for human food, but the new policy will turn this into a requirement, according to Mayers. "As a quality-control measure spinal cord removal was already occurring in federally registered establishments," he said. "Because we're dealing with a public health issue, the announcement of [a ban on] SRMs brings a different level of consideration regarding compliance and enforcement. If there is inadvertent contamination with spinal cord, it would result in a different level of oversight to ensure absence of the material."
Will Hueston, DVM, PhD, director of the University of Minnesota Center for Animal Health and Food Safety in St. Paul, told CIDRAP News that cattle brain and spinal cord have been legal for human consumption in both Canada and the United States until now, "so this is a change." Hueston served on the international team that reviewed Canada's handling of the BSE case. "The argument has been that in the absence of BSE, brain and spinal cord don't represent a risk," he said.
"I believe that in the United States the majority of meat processors are removing spinal cord from the vertebral column, but brain is not routinely removed," Hueston said. "There's not a huge market in the US for brain per se. But it's not currently banned." However, a product that contains brain or spinal cord can't legally be called meat in the United States, he added. Those tissues are permitted in a product category called "mechanically recovered species," he explained.
Hueston noted that the reason the small intestine is considered a high-risk material "is that it's the first tissue that accumulates infectivity in an animal that's orally exposed to BSE. It can happen relatively quickly, 6 months after exposure." It takes another 2 years for infectivity to show up in other tissues, he added.
The Canadian announcement about SRM prompted observers to wonder if the United States would take a similar action, in view of the two countries' extensive trade and other ties and their similar approaches to preventing BSE. At a US Department of Agriculture news briefing that followed the Canadian announcement, officials said only that a similar US move is a possibility.
Hueston commented, "I was under the impression from everyone I've talked to lately that the original idea or concept was that the two countries would announce the approach [to BSE] jointly and have a harmonized approach for North America. It would appear that Canada felt they had to move ahead and take some steps."
In their Jul 18 communique, Canadian health and agriculture officials said discussions are continuing on other possible anti-BSE measures, such as increased surveillance and additional controls on animal feed.
Canadian Food Inspection Agency BSE site
CIDRAP News story on the recommendations of veterinary experts who reviewed Canada's BSE response