discover first signs of BSE in sheep
Scientists have detected the first signs that bovine spongiform encephalopathy (BSE) may have crossed into sheep in a study that is likely to rekindle anxieties over the safety of lamb and mutton.
One of three tests used to determine whether sheep that had seemingly died from scrapie were in fact infected with BSE (also known as "mad cow" disease) has produced positive results. The four-year-old animal was thought to have developed scrapie, a brain disorder that affects sheep and is believed to be harmless to humans.
It died in January and its brain was tested by the Veterinary Laboratories Agency (VLA) in Weybridge, Surrey, as part of a national programme to determine whether BSE has become endemic in sheep. Two of the three tests were negative for BSE but the third gave "some characteristics" that were similar to experimental BSE in sheep, the Department for the Environment, Food and Rural Affairs (Defra) said.
Scientific experts who carried out the tests have nevertheless concluded that the case "could not be considered to be" BSE, although they have not ruled out the possibility that this is the first case of BSE disease in sheep. "Some characteristics [of the test] were similar to experimental BSE in sheep and also to [an] experimental strain of sheep scrapie," Defra said.
It was always theoretically possible for sheep to be infected with BSE because they were once fed the same infected material that had spread the brain disease in cattle during the 1980s and early 1990s. But there is no simple test to distinguish BSE from sheep scrapie, and sheep experimentally infected with BSE show the same symptoms as scrapie, which means that scrapie in the field could be masking a hidden BSE epidemic in sheep.
Scientists at the VLA are now testing the sheep's brain with more a sophisticated method based on long-term mouse experiments, which should within two years determine whether the animal really did have BSE or a simply a new strain of scrapie. Defra said that in the meantime the lack of further evidence to suggest that the animal had BSE as opposed to scrapie meant that the existing rules governing the sale of lamb and sheep offal remained unchanged.
Professor Howard Dalton, chief scientific adviser to Defra, said: "As we continue to assess more samples with these improved methods it is likely that we will continue to find samples, such as this, which fall outside our current knowledge of the disease."
The Food Standards Agency said that until there is firm evidence that BSE is present in the national sheep flock there is no need to change existing rules governing the sale of lamb products, such as intestines, which could carry a higher risk of being infected with BSE.
Experiments suggest that BSE could be easily transmitted to sheep, and it could, like scrapie, be passed down the generations. This would mean that BSE could still be infecting the national flock today, more than a decade after meat and bonemeal was banned.
Trade associations relieved by USDA's Creekstone decision
Daniel Yovich on 4/12/04 for Meatingplace.com
On Friday, Bill Hawks, the Agriculure Department's undersecretary for marketing and regulatory programs, said the agency would not approve the Creekstone plan because it "would have implied a consumer safety aspect that is not scientifically warranted." Creekstone wants to test all of its cattle in a bid to resume shipping its branded Black Angus product overseas, where Japanese and South Korean agriculture officials said it would be welcome ?as long as USDA approved and supervised the testing ?despite Japan's ban on the import of U.S. beef.
American Meat Institute President J. Patrick Boyle said AMI has "respect [for] this decision" and noted that USDA concluded that testing 100 percent of cattle for BSE in a packing plant is "inconsistent with international animal health standards, our domestic BSE surveillance program and the U.S. position in trade policy discussions." The U.S. government has held that USDA's ten-fold expansion in its BSE surveillance program holds up to scientific scrutiny and is sound enough to determine if additional BSE cases exist in the United States.
"It is apparently USDA's view that additional testing beyond this surveillance program is unnecessary and that demands from our foreign trading partners for 100 percent testing are not based on sound science," Boyle said.
Japan and South Korea continue to demand that all U.S. beef bound for export to those countries be tested for the brain wasting disease, and Creekstone might have found itself with an unfair advantage had it prevailed, said Gary Webber, the National Cattlemen's Beef Association director of regulatory affairs.
"We want a level playing field for all companies based on science," Webber said.
But prior to the USDA decision, former AMI Chairman Phil Clemens, the chairman of the Clemens Family Corp. ?the holding company for Hatfield Quality Meats ?said he understands Creekstone's desire to satisfy their overseas customers' requirements that all product be tested.
"I don't have a dog in the fight, but I can understand where Creekstone is coming from on this issue." Clemens told Meatingplace.com.
Like AMI's Boyle, National Meat Association Executive Director Rosemary Mucklow said she too respects USDA's decision.
"It's the government's responsibility to be clear, and they have finally told Creekstone the way they see this issue," Mucklow said. "I think that's the best we can hope for."
Creekstone leaders said late Friday they are considering their legal options in the wake of the USDA decision and were not ruling out filing a lawsuit against the agency for inhibiting the company's ability to earn revenue.
Research Institute annual meeting - Food safety meeting May 18 and 19, 2004
provide compelling evidence of protein-only prion infectivity, and that prion
strain differences must be structural
Innovations in pasteurisation
- 08/04/2004 - New equipment designed to pasteurise food safely and efficiently is being developed to meet EU food safety regulations. We look at two products hoping to capitalise on a growing market.
equipment supplier P Lindberg Industri has developed super microwave ovens capable
of pasteurising food. The first customers are egg packers and milk powder producers,
and the company claims that the meat industry has also showed an interest in the
The principle of the gigantic microwave oven is identical to the one in an ordinary and much smaller microwave oven. A plate rotates in the bottom of the oven, microwaves run through in order for the subject to be heated up quickly it can be heated up to 90 degrees Celsius.
According to Anders Boisen, a computerised giant-microwave measuring three metres in high, three metres in breadth and two metres deep, costs between $244,000 and $330,000 depending on the level of technology each oven is equipped with.
P Lindberg Industri is better known in the food industry for the manufacture of stainless chill tanks, but the company is confident that there is a lucrative market for its giant microwave technology. There is certainly an increased focus on food safety at the moment. New EU food safety legislation comes on line in January 2005, and there are plenty of other innovative pasteurisation products coming onto the market.
Another interesting new product is Leda Technologies patented pasteurisation system that is specifically designed to eliminate Salmonella and high levels of avian flu in shell eggs. The company is currently looking to role the technology out on an industrial scale.
If a large egg producer were to contact us to work on a large-scale industrial process, then that is something we would look into,?communications manager Stejn de Preter told FoodProductionDaily.com. We know we have the technology, and we know how efficient this system is.?
Ledas technology ensures that eggs can be pasteurised in the shell and consequently safely stored for long periods of time. The company claims that the appliance, called Pollux, incorporates traditional means of heat pasteurisation with intelligent software that increases the system ability to ensure food safety.
The firm claims that the system has been independently certified to kill at least 700 million Salmonella bacteria inside shell eggs while not affecting the eggs' composition, appearance, nutritional value, taste or cooking properties.
Egg safety is a growing concern. According to the World Health Organisation, at least 40 per cent of reported food poisoning cases in Europe can be attributed to food containing infected eggs, with Salmonella playing a particularly prominent role. And over the past few months, avian influenza has raised fears even further over the safety of poultry products.
The disease has led to the imposition of severe import restrictions on Cambodia, Indonesia, Japan, Laos, Pakistan, China, South Korea, Thailand and Vietnam. At the end of February, as bird flu surfaced in Texas, the EU halted all poultry related imports from the United States. Last years bird flu epidemic in Belgium, the Netherlands and Germany led to the cull of 30 million chickens.
Food Safety Informaiton
BSE-like disease found in sheep
Britain's Department for Environment, Food and Rural Affairs has announced that the Veterinary Laboratories Agency in Weybridge, England, had found "a type of scrapie not previously seen in the UK". Scrapie is a sheep disease similar to BSE which is not generally thought to harm people.
DEFRA said the disease-causing prion detected in the sheep's brain "had some characteristics similar to experimental BSE in sheep", but that on other tests it resembled neither BSE nor "previously recognised types of scrapie".
The UK's Food Standards Agency said in a statement: "Uncertainties still remain on this issue. However, based on the best scientific evidence to date, we are not advising against eating lamb and sheep meat."
Meat and bone
There have long been fears that sheep which ate cattle-derived meat and bone meal during Britain's BSE epidemic in the 1980s might have acquired BSE, although they have never been confirmed.
Unlike BSE in cattle, prion diseases spread directly from sheep to sheep. So any BSE in sheep could still be circulating despite subsequent bans on animal-derived feed.
Furthermore, sheep experimentally fed BSE develop a disease indistinguishable from ordinary scrapie, making detection very difficult. Yet the prion from such animals still behaves like BSE, and could cause the fatal human disease vCJD.
Worse, sheep carry prions in more tissues than cattle, including the muscle that people eat, so BSE-infected sheep could cause more human disease than mad cows.
A previous attempt to determine whether British sheep acquired BSE went spectacularly wrong in 2001 when sheep and cattle brains were mixed up in the lab. But since then, the VLA has tested the brains of all 1019 newly reported cases of scrapie, as well as 1125 scrapie brains dating back to 1998, with tests designed to distinguish scrapie from BSE.
The new result announced on Wednesday, from a sheep recently reported with scrapie symptoms, is the first to give results that resembled BSE. Danny Matthews of the VLA told New Scientist that in a prion test called a western blot, the sheep's brain did not bind an antibody called P4. P4 also does not bind prions from sheep experimentally infected with BSE, but does bind all but one forms of scrapie tested with it.
Also like BSE, the form of the prion without a sugar attached to it had a lower molecular weight than the form found in scrapie. But the ratio of prions with different numbers of sugars on them looked like scrapie, not BSE, says Matthews.
Most conclusively, immunohistochemistry (IHC), in which thin slices of the sheep's brain were stained with various antibodies, showed prions had accumulated in different parts of the brain and different kinds of cells from BSE - or any known form of scrapie.
The IHC pattern reliably indicates BSE, says Matthews, having been constant in the 100 experimentally infected sheep of different genetic varieties tested so far. But so little scrapie has been tested, he says, it is not known if one strain might give these results on the tests.
One possibility, he says, is that the sheep might have been carrying a prion initially derived from BSE. Passage into new species is well known to change prions.
BSE from experimentally infected sheep has so far been passed to just one more round of sheep, with no apparent change. "But we don't know if passage through many sheep, of different genetic types, might change it so it no longer gives the same pattern in IHC or western blots," says Matthews. "Those experiments are underway now."
Any such new incarnation of BSE in sheep may - or may not - have lost its ability to harm humans.
method to detect dioxin in fish
Third [Rapid BSE] Test Approved
Abbott Laboratories has received USDA approval for its rapid BSE test.
Abbott Laboratories, Abbott Park, Illinois, has received approval from USDA to sell and distribute its rapid Enfer BSE test for the detection of bovine spongiform encephalopathy infection in cattle. The rapid test provides results within hours, is easy to use, and addresses the workflow needs of USDA-approved screening laboratories, the company said in a release. The Enfer BSE test detects the presence of the abnormal proteins ?prions -- believed to cause BSE in brain tissue.
Enfer BSE test has been successful in Europe and Japan, where large scale screening
is mandatory,Joseph Nemmers, senior vice president of diagnostic operations at
Abbott, said. As a leader in diagnostic testing and blood screening, we will continue
to work with the USDA and offer this high quality test as part of an overall BSE
rapid Enfer BSE assay tests every bovine brain sample in duplicate,Jim Koziarz,
Ph.D., vice president of research and development, diagnostics at Abbott, said.
If either test result is reactive, the brain specimen is resampled and retested
in duplicate. This type of testing method ensures that a true positive would be