Japanese authority's recommendation to stop testing imports of U.S. beef from young cattle for mad cow disease was a "very small step" in a process that was still too slow and cumbersome in lifting a wider ban on American beef, U.S officials said.

Japan's food safety panel on Monday recommended the government stop testing cattle younger than 21 months for mad cow disease, a cautious step toward ending a ban on U.S. beef imports imposed in December 2003 after the United States (search) found a case of the disease.

Tokyo (search), seeking to soothe worries at home about a domestic mad cow outbreak, has refused to reopen its market to U.S. beef products until Washington adopted blanket testing for the disease.

But the Food Safety Commission's (search) scientific experts said research has shown that rogue proteins linked to the disease don't show up in tests on cattle younger than 21 months, and that easing the testing standards wouldn't put consumers at risk.

U.S. officials called Monday's development a step in the right direction, but said that Japan should speed up the process.

"It's a very small step. But we still think the Japanese process is going far too slow, and it's unnecessarily cumbersome. We would like to see it accelerated," said J.B. Penn, undersecretary of the Agriculture Department's Foreign Agricultural Service.

Since discovering its first case of mad cow disease in 2001, Japan has tested every cow slaughtered as food for the bovine illness to reassure consumers jittery about food safety. Tokyo has found 16 animals with the disease, most recently a Holstein cow on Sunday.

Monday's panel ruling marked the first time Japanese experts have agreed with the assessment of U.S. scientists — a key step that allows Tokyo to begin debating standards for U.S. beef imports.

But the Japanese panel also acknowledged that not enough is known about the disease, formally called bovine spongiform encephalopathy, to rule out all risk.

Eating beef from an infected cow is thought to cause the fatal human variant Creutzfeldt-Jakob disease.

The ban has been costly for American beef producers who sent an estimated US$1.7 billion (euro1.3 billion) of beef products annually to Japan — the most lucrative overseas market.

Recently, Washington has intensified pressure on Tokyo over the issue, with some U.S. lawmakers threatening possible sanctions if the ban isn't lifted soon.