Prions
Mad Cow Home or Best Links

Worry Over Mad Cow Risk Prompts Slaughtering Method
Stunning scatters brain tissue through body
Humane slaughter review Gap in Mad Cow firewall?
Swiss report two new cases of mad cow disease
Tracking cattle online
UK may seek to lift EU beef ban for N. Ireland
Speculation on origins of BSE: rendered meat from Africa?

Worry Over Mad Cow Risk Prompts Slaughtering Method

 Thu, Jul 24, 1997  DJ (Dow Jones)  By Sarah McBride
The meat industry said it would study a widely used cattle-slaughtering procedure after researchers found it may spread brain tissue -- one of the tissues most likely to be infected with mad cow disease -- to edible parts of the animal.

Preliminary findings by Texas A&M University researchers and Canadian scientists show that brain particles have been spread to the lungs and liver after cows have been stunned with a pneumatic gun, which uses an explosive burst of air that scatters the tissue.

Researchers from Colorado State University plan to launch the study in September and announce results by year's end. The American Meat Institute Foundation and the National Cattlemen's Beef Association will fund the approximately $150,000 project; they are asking the Department of Agriculture to review the protocol.

It's unclear exactly how the brain tissues end up so far-flung. They are found in blood vessels, but are often too large to be transmitted through normal circulation.

"The belief is that the air pressure causes almost a backflow of tissue [through blood vessels] during the time the animal is hung up, before it is drained" of blood, said Janet Collins, the foundation's vice president for science and technology.
The study's first phase will evaluate various types of stunning methods; the second will compare blood and tissue samples from cattle stunned before slaughter and from cattle that weren't stunned, and the last phase will analyze the results of stunning on edible portions of the cow, including organs.

Most cattle are stunned to ensure they are unconscious before slaughter, as required by a humane-slaughter law, although not all stunners are the powerful pneumatic type. Exempt from stunning are halal meat, prepared according to Islamic law, and kosher meat, representing less than 5% of the U.S.

market. Alternatives to pneumatic-gun stunning include cartridges, which are similar to bullets, and captive bolts, which puncture the head before being quickly withdrawn. Electric stunners are another possibility, but are little used in the U.S. because of concerns for worker safety, said Ms. Collins.

Mad cow disease, or bovine spongiform encephalopathy, has been an agricultural problem and public-relations nightmare in Britain, but it has never been found in the U.S. In Britain, where pneumatic stunning isn't commonly used, cows contracted the disease after eating feed containing ground-up parts from diseased animals. The bigger concern came recently, when the British government acknowledged that eating meat from tainted cows may have led to 18 human deaths there and in France from a new strain of a rare disease known as Creutzfeldt-Jakob Disease, which is a brain-wasting ailment similar to mad cow disease.

Researchers from the University of Edinburgh in Scotland are trying to establish a direct link between mad cow disease and the new variant of CJD. Their findings will be announced later this summer. Abnormal prions, proteins found naturally on brain cells, are believed to be the cause of mad cow disease and CJD.

US consumer group says gap in Mad Cow firewall

 Reuters Financial Report 
 Thu, Jul 24, 1997
WASHINGTON - Stunners used on cattle before slaughter can send brain tissue scattering through the animal's body, raising concerns this could become a route for Mad Cow disease to enter the food supply, a consumer group said Thursday.

At a news conference, the Center For Science in the Public Interest pointed to recent research on the subject by Texas and Canadian universities. Representatives of the meat industry participating in the news conference said they would conduct their own study this fall. The study will be sponsored by the American Meat Institute Foundation and the National Cattlemen's Beef Association. The groups said they would have their protocol reviewed by U.S and Canadian government agriculture officials and expected results before the end of this year.

Stunning scatters brain tissue through body

July 25, 1997
Listserve Commentary on Washington Post/AP/Wall Street Journal/Reuters
John Schwartz
Press conference called by the U.S. Center for Science in the Public Interest (CSPI) in which they warned that a method used commonly to prepare cattle for slaughter, called "stunning," could let "mad cow disease" eventually enter the U.S. food supply. However, the group also said there is no imminent risk to Americans because no cases of BSE have ever been detected in the United States.

Nutritionist David Schardt of CSPI was cited as saying that if BSE were to appear in the United States, stunning could be a route for its spread from cows to humans, calling the practice "a hole in the fire wall" protecting humans from the disease.

Pneumatic stunning of bovines, and the possible forced introduction of brain tissue into the rest of the carcass through the venus return circulation in the last seconds of life: although traditional stunning using a Cash's captive bolt piston may not "blow" compressed air into the skull, but the "pithing" rods introduced immediately after the shot (to destroy the medulla oblongata at the base of the brain) would probably also allow a brain tissue-slurry to recirculate for a few moments.

Stunning was described as a decades-old practice, designed to incapacitate cattle while protecting slaughterhouse workers, which renders the animal brain-dead by sending a power-driven plunger through its skull. Because stunning is generally considered to be a humane way of preparing cattle for slaughter, some form of the procedure is required by the federal Humane Slaughter Act.

The process, especially a pneumatic variant that follows the plunger with a blast of air, appears to drive particles of brain matter through the animal's circulatory system. Last year, researchers at Texas A&M University announced that they had found brain tissue in the lungs of as many as as 5 per cent of cattle that had been stunned. At the time, the meat industry said that the findings did not have consequences for public health since Americans generally do not eat lung tissue.

However, Schardt was cited as saying that new research by the Texas researchers and the Canadian government's Food Inspection Agency has found bits of brain matter in liver and other parts of the body as well, adding that "It splatters brain tissue, as it turns out, throughout the cow's body," Those observations, notes the Post story, have not yet been published in a peer-reviewed scientific journal, so they must be considered preliminary.

The story goes on to cite industry estimates as saying that the more forceful pneumatic method of stunning is used by 75 per cent of slaughterhouses that process more than 50 heads per hour, according to industry estimates. A recent review of stunning procedures by assistant professor Temple Grandin of Colorado State University and cited in the Post story suggested that the pneumatic process increased the probability of contamination, especially when the creature is stunned more than once, which she said "pulverizes the brain."

The process is prohibited for kosher slaughter, although Grandin found that those procedures might pose their own risk of transmitting infection because they cause more "bloodsplash" than captive-bolt stunning. Grandin wrote that a slightly costlier method, using small, hand-held, cartridge-fired guns, improved aim and decreased bloodsplash. "If air injection proves to be the major cause, the problem can easily be eliminated by using a well-maintained cartridge gun," Grandin wrote.

The story notes that representatives of the American Meat Institute and the National Cattlemen's Beef Association appeared at the press conference called by CSPI. Although neither organization acknowledged that the stunning process is a source of risk to humans, they did announce that they would sponsor a study on stunning that should be completed by early December. Janet E. Collins, vice president for research at the American Meat Institute Foundation was quoted as saying that "The industry is committed to finding a better way if there is a problem," but added, "Before you can make the statement that you have a problem here you have to have the data -- and I don't think that the data are good."

One story noted that researchers from Colorado State University plan to launch the study in September and announce results by year's end. The American Meat Institute Foundation and the National Cattlemen's Beef Association will fund the approximately $150,000 project; they are asking the Department of Agriculture to review the protocol.

The study's first phase will evaluate various types of stunning methods; the second will compare blood and tissue samples from cattle stunned before slaughter and from cattle that weren't stunned, and the last phase will analyze the results of stunning on edible portions of the cow, including organs.

Note that only one type of stunning method has this problem. The impact energy liquifies the soft brain, which is transmitted throughout the body (principally the lungs) by the still beating heart.

Where "The Knocker" method is practised, it is a matter for concern, but it has been so since June 1996, and it is not prudent to ignore it just "because no cases of BSE have ever been detected in the United States". No surveillance scheme, however thorough, can prove a country BSE-free. It is good to see that the US industry representative bodies are taking it seriously.

Last year's Texas A&M University research on this subject did have considerable publicity, generally and here in the UK. It was originally presented at the USDA Scrapie/BSE Consultants' Group Meeting at Ames, Iowa in June 1996 and was later published in The Lancet [Garland et al (1996) "Brain emboli in the lungs of cattle after stunning", Vol 348, August 31 1996, 610].

At the time, it was categorically stated, by the (UK) Meat & Livestock Commission, and confirmed to me by Dr Tom Toomey (see below) that the method described was not in use in the UK. The UK agent of the only company producing the equipment indicted by Texas A&M ["The Knocker", by Hantover] confirmed that they had not supplied it to anyone in the UK.

As regards 'pithing', in a paper that Toomey gave at a symposium at Heathrow in February 1996, he stated

"Under modern slaughtering conditions it is considered that 'pithing' is unnecessary if effective stunning is carried out".
What happens to the infected carcasses of diseased laboratory animals and organs (such as brains) that were used for passage studies? Were they incinerated (as they would be now) or were they just sent conveniently to the knacker yard? Compton incinerates *everything* that went through that lab. This even included work on animals carrying animal diseases that were at that time quite common (like IBR) and even if the animals were controls. They have a massive incinerator on site, it was already old in 77/78.

UK may seek to lift EU beef ban for N. Ireland

July 31, 1997
Reuter
LONDON -- U.K. agriculture minister Jack Cunningham was cited as telling the Financial Times on Thursday that he hopes to win exemption for Northern Ireland as the first step in lifting a European Union ban on British beef exports, adding that Northern Ireland had a "powerful case" for an early lifting of the ban for beef from herds certified free of BSE. Northern Ireland has a very low incidence of the disease and a computerised cattle base to trace animal movements.

But the report noted that Cunningham's plan might bring him into conflict with ministerial colleagues representing Scotland and Wales, which both have strong farming lobbies.

Swiss report two new cases of mad cow disease

 Reuters North America 
 Tue, Jul 29, 1997
GENEVA (Reuter) - Switzerland reported two new cases of mad cow disease Tuesday, bringing the total to 25 so far this year. The Federal Veterinary Office said both cases of bovine spongiform encephalopathy (BSE) had been reported in the canton of Appenzell in German-speaking Switzerland.

The affected animals were born after the ban on the use of cattle feeds containing meal made from animal remains, which took effect in December, 1990, it said in a statement. It did not say how the cows had been infected or give details.

Public concern about infected beef has been growing since British scientists found evidence in March 1996 that mad cow disease could be transmitted to humans as the brain-wasting Creutzfeldt-Jakob disease (CJD). Scientists believe BSE was spread by the practice of feeding animal by-products to cattle. So far, some 30 countries have imposed restrictions on Swiss cattle and beef imports. Mad cow disease is most widespread in Britain with more than 167,000 cases reported in the past 10 years.

Origins of BSE traced to herds of the African plains

The Independent, Aug. 1, 1997
Charles Arthur, Science Editor
Mad cow disease may have originally been brought to Britain in a shipment of infected animal remains from Africa, according to a growing body of scientific evidence. Though this contradicts the Government's line, stringently maintained for the past decade, that the disease originated in diseased British sheep which were recycled into cattle feed, it fits a wealth of data which was not available when the diagnosis was first made in 1985.

If correct, it means that many precautions now being taken at great expense by the Government - for example, destroying sheep offal - are unnecessary, because scrapie would not pose a risk to humans or cattle. It also has implications for imports of foodstuffs from foreign countries where unusual diseases may occur, and precautions needed to stop their spread.

But John Wilesmith, the government scientist who in 1987 pinpointed infected cattle feed as the means by which BSE was spreading, said last night: "I think as events have gone on, the scrapie hypothesis still bears the test of time." He added that he was worried that any concentration on alternative sources of the epidemic could distract from introducing controls on recycling animal offal in Europe. "If they aren't, there could be more cases [of BSE]," he said.

Key in the new evidence is a written Parliamentary answer given by the Government yesterday, showing that between 1970 and 1980 the UK imported thousands of tonnes of meat and bone meal from various African countries, including South Africa, south western Africa and Botswana - which has a significant cattle industry. The imports effectively stopped afterwards.

Previously, scientists have shown that many African zoo animals such as cheetah, kudu, nyala, gemsbok, eland and oryx can catch BSE - increasing the chance that it originated among them. Some wild animals like elk and deer develop BSE-like diseases spontaneously [never shown -- these are more plausibly from scrapie of BSE -- webmaster], but it has never been observed in cattle before the epidemic, which began in 1985.

The new hypothesis will not alter predictions for the final number of people who may die from the "new variant" of the fatal brain disorder Creutzfeldt-Jakob Disease (CJD), which has so far affected 19 people. They almost certainly got it by eating BSE-infected cattle products.

Previously, the takeoff of BSE in 1985 was blamed partly on deregulation by the incoming Thatcher government in 1979 of the rendering industry (which strips useful elements from cattle and sheep carcasses).

It was claimed that rule changes allowed lower cooking temperatures, which did not destroy the BSE disease agent. That was then fed back to cattle as infected bone meal. But subsequent investigation has shown that rendering practices were unchanged from the late 1960s. Dr Wilesmith agreed: "Rendering hadn't changed - that's rubbish."

Thus the system to "amplify" BSE by recycling dead, infected carcasses was in place throughout the 1970s. Yet scrapie-infected sheep were entering the rendering system. If scrapie were the cause of the BSE epidemic, it could have started in the 1970s or early 1980s.

Questions arising:

1. Who asked for the African MBM tonnages in Parliament, as mentioned in
the article?

2. What were the numbers and dates involved? Any other information in the
government response?

African rendering data and general rendering information:

Protein supplements are the residues of meat scraps and trimmings after the fat has been extracted. Each of the methods of extracting fat yields a slightly different protein concentrate. To avoid the spread of foot-and-mouth disease, the material should be subjected to a boiling temperature for at least one hour during processing.

1. Wet rendering involves a higher temperature than other methods and therefore yields a concentrate of slightly lower protein value. The tissues are placed in a tank, water is added and steam is injected directly into the bottom of the tank. The fat cells are ruptured by the high temperature and the free fats float to the surface, where they are skimmed off. The cooking water is drained off into a container, and the wet protein residue is pressed to remove additional fat and then dried. The cooking water which is rich in dissolved protein is evaporated and either used separately for feeding or added to the dried protein residue. Blood may be added to the protein residue to increase its protein content. The protein concentrate obtained by this method is called "digester tankage" or simply "tankage." Generally the conversion rate of raw material to dry meal is 4:1.

2. In dry rendering the meat scraps are heated in an open cooker, usually a horizontal steam-jacketed tank equipped with an agitator. After the tank is loaded, the steam is turned into the jacket to heat the contents. The heat breaks down the fat cells and evaporates the moisture. When all the water has evaporated, the steam is turned off and the content of the tank is dumped into a percolating tank, where the free fat is drained out. The remaining protein residue, called "meat cracklings," is usually further processed to remove more of the fat either with a press or a solvent extractor. The protein concentrate obtained with this method is called "meat meal." If so many bones have been added that the phosphorus content exceeds 4.4%, or if the crude protein content is below 55%, the product is called "meat-and-bone meal", or if made from condemned whole carcasses, it is known as "carcass meal." Generally the conversion rate of raw material to dry meal is 3:1.

3. Where there are no rendering facilities, the meat from condemned animals and offals, including washed intestines, should be cut into small pieces and cooked for at least one hour. This can be done in an oil-drum which has been cut in two along its longitudinal axis. After one hour's cooking the bones are removed, and wheat middlings and rice bran are added in equal weight to the mass and stirred in. This mixture is boiled for a half hour to give the final product a thick consistency. It is fed to pigs the same day or at most the day after it is prepared. USE. Meat meal and tankage are most widely used in feeds for poultry and pigs. They are usually too expensive to feed to ruminants, which in any case generally find meat products unpalatable. Because of the usual high price of meat meal and tankage, they are used to balance the amino-acid composition of diets rather than as a major source of protein. High levels of meat products in pig diets should be avoided, as an excess of calcium will disturb the zinc balance. Normally less than 5% meat meal and tankage are used in growing and finishing diets for pigs and less than 10% in diets for brood sows and poultry. Important unidentified growth factors for monogastric animals have been attributed to meat products. There is a wide variation in the composition of meat meal and tankage depending on the ratio of muscle tissue and connective tissue in the raw material. The biological value of connective tissue is much lower than that of muscle tissue.

Tracking cattle

 Thu, Jul 31, 1997  By Jo Butler, Consumer Affairs Correspondent, PA News
A computerised tracking system to trace every cow and bull in Britain will be up and running next year, the Government announced today. The British Cattle Movement Service, to be based at Workington, West Cumbria, is aimed at giving the UK one of the most advanced traceability systems in Europe.

Announcing details of the system, food safety minister Jeff Rooker said he hoped it would restore confidence in British beef and help persuade the EU to lift the ban on beef exports. The system will trace the movements of all cattle in Britain, backing up paper cattle passports which are already in use. An on-line system is in place in Northern Ireland. Mr Rooker said the 1998 target date was ahead of a 1999 deadline the EU has set for all member states to install similar computers. The system will allow abattoirs and auction markets to input data to a central database. Mr Rooker said:

"With this new system, we aim to be one of the leaders in Europe on cattle traceability. "It will play a vital part in restoring European confidence in British beef. "It will employ over 100 local people who will be in charge of handling information on more than 20 million cattle movements every year."
As revealed in Parliament on Wednesday, the service is to be based at Workington in West Cumbria. The National Farmers' Union said news that the scheme was making progress was very welcome, and a vital part in the battle to rebuild consumer confidence in British beef.

The U.K. Government was cited today as announcing that the headquarters of its new British Cattle Movement Service -- aimed at tracing the background and lineage of cattle to prove they are BSE-free -- will be at Workington, Cumbria -- creating more than 100 jobs.

UK News Briefs

July 30, 1997
PA News
Andrew Evans
U.K. junior agriculture minister Lord Donoughue was cited as saying today that consumer representatives are to have seats on the BSE committee and other expert committees advising the proposed new Food Standards Agency.

BRUSSELS -- The European Commission today, according to this story, banned the use of animal tissue carrying any potential risk of BSE, effective January 1, 1998, and applies to the skulls, eyes, brains, tonsils and spinal cords of cattle, sheep and goats over 12 months old and the spleens of all sheep and goats. The Commission said in a statement that the decision was a precautionary move designed to protect humans and animals from any risk of BSE.

U.K. Tory Christopher Gill (Ludlow) was cited as telling the Commons today that more beef farmers will commit suicide or die of stress this year because of coping with BSE control measures than the total of people who will die from nvCJD, adding that, "Surely, this is a case if ever there was one where the cure is infinitely worse than the disease."

FSIS initiates humane slaughter review

July 28, 1997 NMA - Lean Trimmings by Erica Smith
The Center for Science in the Public Interest (CSPI) held a press conference last week in Washington, D.C. to question whether stunning practices used in cattle slaughter may be spreading brain tissue throughout the animals body and therefore increasing the chance of Bovine Spongiform Encephalopathy (BSE) entering the food supply.

A researcher at Texas A&M, in collaboration with an FSIS employee at the College Station training center, announced last year that brain tissue had been found in the lungs of stunned cattle. A new study by Texas A&M and the Canadian governments food inspection agency shows that brain tissue has been found in the liver and other parts of the body as well.

Although BSE has never been discovered in the U.S., CSPI hypotheses that if BSE were to appear in the U.S., stunning could be a route for its spread from cows to humans.

NMA subsequently learned that FSIS has initiated a special humane slaughter/ante-mortem/central nervous system disorder review. FSIS is conducting the review in response to formal inquiries raising questions about ante-mortem inspection, BSE and CNS disorders. The first component of the review will address whether official establishments are adhering to the component of the Humane Methods of Slaughter Act of 1978.

The second component of the review will focus on whether current ante-mortem procedures, as specified in the regulations, are sufficient to identify CNS disorders in livestock. After developing a checklist and review protocol, the review staff will conduct on-site visits to slaughter facilities and use a hands-on observation/interview approach to review humane handling and ante-mortem inspection procedures and associated records. The review team will also observe both FSIS and plant personnel in the performance of these procedures. Members with questions should speak with NMAs Director of Regulatory Service Ken Mastracchio.

Mad Cow Home or Best Links