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Mad cow testing: How much is enough?

Across Europe, aggressive testing of cattle is coming up with many cases of mad cow disease:  183 in Ireland last year;  54 in Germany. But how much testing is enough?
Under a U.S. Department of Agriculture plan announced last week, some 200,000 cows -- one in every 185 killed -– will be checked for bovine spongiform encephalopathy.Elaine Thompson / AP file

As goes California, it is said, so goes the nation.  In that case, the meat industry probably isn’t too happy about plans by lawmakers there to test every bit of beef in the Golden State for mad cow disease.

Not just California cows, but any cattle sold as meat to the state’s 35 million residents -- tens of millions of pounds of beef from across the West and potentially across the nation.

As chair of the California Senate's agriculture committee, State Sen. Michael Machado estimates the plan would cost a modest two cents per quarter-pound hamburger. Given the disease’s fatal nature, he believes the plan makes us safe -- instead of very sorry.

“The fact that we’ve only been able to discover one cow has not been a cause for alarm,” says Machado, referring to the single U.S. case of the disease discovered in Washington state in December. "What can we do in terms of a greater sense of confidence in that food supply?"

Many more tests
Last week the U.S. Department of Agriculture announced a plan for heightened mad cow testing. It doesn't go nearly as far as the California proposal would, but even critics see it as a huge improvement.

Under the USDA plan, some 200,000 cows -- one in every 185 killed -– will be checked for bovine spongiform encephalopathy. That's 10 times the number tested last year.

Most tests will focus on cows considered at highest risk of BSE: animals that cannot walk, have nervous-system disorders or die on the farm.  But about 10 percent will be healthy, older cattle, chosen from specimens at major U.S. slaughterhouses.  This dual approach, officials argue, can best detect whether the disease has spread into the U.S. cattle population.

But is it enough to keep us safe?

USDA Chief Veterinarian Ron DeHaven quoted estimates from the Harvard Center for Risk Analysis that the new plan will provide at least 95 percent confidence that no more than one in 10 million cattle has BSE -– no more than five stricken cows in the whole country. (The Harvard group also prepared a now-debated 2001 assessment of U.S. mad-cow risks.)

If all cattle were considered equally at risk, random testing of the 45 million U.S. adult cows  would, by the USDA’s own calculations, require testing 3 million head each year to be 95 percent sure the disease hadn’t spread beyond the one-in-a-million mark.

Government and industry officials are quick to note that even before the discovery of mad cow in the United States last December, the U.S. surveillance far exceeded guidelines from the World Organization for Animal Health.

That organization, which sets global animal testing standards, suggested at least 433 U.S. animals be tested each year.

However, that recommendation described a baseline for the most basic of surveillance programs in a country untouched by BSE. It was designed for risk assessment, not prevention, and the only the sickest cattle were targeted.

Testing healthy animals
But not everyone agrees the disease can be found just by checking only sick animals. “That’s just not true, looking at Europe and elsewhere,” says microbiologist Michael Hansen, who studies animal diseases and food safety for Consumers Union.

Admittedly, Europe finds many of its cases in high-risk cows. Of Ireland’s 183 cases last year, just 31 came from random tests of healthy cattle.

Yet most European nations test cows at far higher levels than in the United States and Canada, and regularly turn up positive cases in older healthy cattle. Germany tested nearly 2.6 million of the 4.3 million cattle it slaughtered last year. Of 54 positive cases, 21 were in healthy cows. It helps explain why the European Union requires tests for all cows over 30 months.

Numerous cases have been found in younger cattle, too. A 23-month-old Japanese bull tested positive last fall. Britain, where over 180,000 cases of the disease devastated the cattle population in the 1980s and 1990s saw numerous cases at 24 months and reported one at 20 months. France and Germany now test all animals for human consumption older than 24 months.

“You do find some in the healthy population, period,” says Fabio Rupp, North American representative for Swiss firm Prionics, which manufactures BSE tests used in several countries, including Canada.

The extra tests can be chalked up to stricter laws, along with Europe’s tendency to let cattle grow older before slaughter.

U.S. government officials, and the U.S. beef industry, have dismissed calls for such requirements, and have almost palpable contempt for measures like those in Japan, where every one of the 1.1 million cattle slaughtered last year was tested before it could be eaten.

“All these increased numbers do is to give you a higher degree of statistical confidence,” says Jim Hodges, president of the American Meat Institute Foundation, which represents U.S. meat packers.

Few firm numbersTheir frustration is understandable. Japan was the first of dozens of nations to halt imports of American beef after the first U.S. mad cow case was found Dec. 23. Most want far more testing than the USDA’s new plan calls for. Beef producers have stood their ground against expanded testing, quick to note that the USDA’s increased testing is a one-time effort, not an ongoing plan.

Almost no one in the industry will outline what they consider to be appropriate testing levels. “I’m not going to play a numbers game,” Hodges says.

The government won’t set a benchmark either, even when the USDA unveiled its plan after two months of work. DeHaven set a target between 201,000 and 268,000 cows, including 20,000 healthy cows, but those numbers aren’t firm goals. And testing plans could again be in flux with the resignation of Bobby Acord, chief of the USDA's Animal and Plant Health Inspection Service, who stepped down Tuesday. Acord had been an opponent of broader testing.

Yet the numbers gap remains between Europe and North America. And advocates of broader testing -- for consumer safety, not just surveillance -- are troubled by questions surrounding the health of the one infected U.S. cow found so far.  While the USDA originally described it as a "downer" that couldn't walk, others say it was perfectly healthy, and its discovery a fluke.

“One does get concerned," Machado says, "when we realize that cow was discovered by accident.”

Read part two: Animal health or food safety --