On discovery of the first US case of BSE, Creekstone Farms Premium wanted to test all of its cattle that it intended to ship to Japan, with the importers agreeing to cover the additional cost.

But the USDA wants to prevent it from doing so. Current BSE testing is only conducted by the USDA on about one per cent of all cows slaughtered in the country.

Private testing on all cattle exports to Japan could force other processors to follow suit, and lead to domestic calls for increased BSE screening of meat products.

While, Creekstone claims full testing will assure its customers of the safety of its products, the USDA contends that this gives a false sense of security because BSE is generally undetectable in younger cattle.

Many large processors in the meat industry are looking on anxiously at the case, as it could set a precedent, eventually forcing them to have full screening procedures for all the cattle they slaughter.

In March, US District Judge James Robertson ruled in favor of Creekstone Farms stating that "prohibition of the private use of rapid test kits to screen cattle for bovine spongiform encephalopathy is unlawful."

The ruling was to take effect June, 1 2007, but the USDA said it would appeal on Tuesday, which now effectively delays testing until this court proceedings are concluded.

A decision in favor of Creekstone would allow the Kansas-based processor to test all of its cows for signs of the condition. If the processor's case ultimately fails, BSE testing will only be conducted by the USDA, which currently tests about one per cent of slaughtered cows.

Dennis Buhlke, president and chief executive officer of Creekstone yesterday said the company has taken a lead role in the issue and is not alone in believing that the government should not prevent private companies from voluntarily testing cattle for BSE.

"Although we are disappointed, we are not surprised by USDA's decision to appeal," she said. "In refusing to allow Creekstone Farms to respond to its customers' preference for beef from animals that have been tested for BSE, the USDA is doggedly pursuing a course that scientists, consumer groups, trade associations and business, and members of Congress regard as a bad policy."

Officials claim that while Creekstone can manage to test each of the 300,000 animals it slaughters each year, larger processors handing millions could not cope. Allowing Creekstone to test would be unfair competition, the USD claims.

"We still hope to convince USDA to work with Creekstone on a voluntary BSE testing program," Buhlke said. "However, Creekstone Farms will continue to pursue our right to test even in the wake of this latest action by the USDA."

Meanwhile, Creekstone said it has built, with the advice of BSE-testing experts, a state-of-the-art laboratory, which is ready for operations at its Arkansas plant.

Last month, Japan eased inspection requirements on shipments of US beef imports into the country, which had been in operation following the discovery of BSE in 2003.

Prior to 2003, the Japanese export market was one of the US's largest, valued at $1.4 billion a year, according to the US Meat Eport Federation (USMEF).

Since the first discovery of the disease in the UK during 1986, some 190,000 cases have been reported worldwide, according to World Organisation for Animal Health (OIE) statistics.

Of the countries affected by the disease, the US ranks low, with only two confirmed cases up to 2006, according to OIE, which recently lowered the country's BSE status to "controlled risk."

Scientists believe that the human illness, Variant Creutzfeldt-Jakob Disease (vCJD) - recognised in 1996 - is caused by the consumption of BSE-infected meat. About 160 people are thought to have died of the condition worldwide.