Tokyo ? Stunned by its first case of mad cow disease two years ago, Japan spent tens of millions of dollars winning back consumer confidence with a system to test every cow for the brain-wasting illness before slaughter.

Now, Japanese people may hold U.S. beef producers to a similar standard.

“Unless the United States can offer the same kind of safety guarantees, I wouldn’t want to buy American beef even if it is allowed back on the market,” said Atsuko Hirano, a housewife in her 40s. “You’ve got to be able to trust what you eat.”

Japanese officials have not publicly demanded the United States put identical safeguards in place before lifting an import ban slapped on American beef last week.

But Hirano’s comments at a Tokyo supermarket illustrated the tough sell facing the United States in a country that is the biggest customer for its beef.

Japan quickly banned imports of U.S. beef after last week’s discovery of bovine spongiform encephalopathy, or BSE, in a single cow in Washington state, slamming shut a market worth $1 billion.

U.S. officials in Tokyo briefed Japanese officials on the mad cow incident Monday. The scare has raised questions about testing methods in the United States, where officials screen only cattle that show symptoms of the disease. The disease tends to show up in older animals, which is why European nations check all cattle more than 30 months old.

U.S. agriculture officials have insisted current safeguards are “appropriate” and suggested comprehensive screening would be unnecessary and costly in the United States, which slaughters about 35 million cattle a year — dwarfing the 1.3 million processed in Japan.

“We do not think that 100 percent testing, such as Japan has, is warranted in any country,” David Hegwood, a senior official who led the U.S. delegation to Tokyo, told reporters Monday.

A veterinarian examines a Holstein cow at a cattle farm in Chiba, Japan, east of Tokyo. After the first mad cow disease was discovered in the United States, Japan, its largest importer, banned the import. Japan began in 2001a system under which all cattle bound for slaughter are tested for the brain-wasting disease. This is the world's most stringent safety measure to satisfy and win consumers' reassurance over domestic beef.

But the reception he got here suggested Washington will almost certainly have to make some concessions. Japanese officials said they would not have discussions on lifting the ban until they know more about the case. A fact-finding team will be sent to the United States next month.

Hegwood insisted current U.S. surveillance was “very effective” but said authorities were “looking at everything we can to make it even better.”

Media reports this week have suggested officials here want Washington to put a system in place that would be as safe as the Japanese one, though not necessarily identical.

“Ours is the strictest system in the world,” said Gaku Yoda, an agriculture official. “We had to convince consumers they are absolutely safe.”

The Japanese mad cow experience shows how difficult that might be.

The first cow to test positive for the disease outside of Europe was discovered on a farm near Tokyo in September 2001, starting a panic that thinned crowds at restaurants, left store shelves cluttered with unsold beef and sent farmers’ profits plummeting as much as 80 percent.

A government panel investigating the outbreak heaped blame on regulators, revealing the Agriculture Ministry had failed to heed a warning by the World Health Organization in 1996 to ban meat-and-bone meal.

Instead of a ban — a measure taken by the United States in 1997 — the ministry initially issued only a lukewarm recommendation that cattlemen refrain from using it.

Stung by criticism, Japan finally banned the suspect feed and announced a month after the outbreak it would screen all cattle bound for human consumption.

The new policy wasn’t cheap.

Japan had to equip about 120 meat hygiene-inspection centers with testing kits imported from France and increase the number of inspectors, spending about $65 million in the first two years of the program just on testing and upgrading facilities, according to the Health Ministry.

Authorities also spent millions more recalling meat and destroying cattle.

Doing the same in the United States, where just 20,000 animals were tested for the disease last year, would be even costlier.

People here insist, however, that in the Japanese case, nothing less than blanket testing would have satisfied Japanese consumers — especially because bungling by authorities was blamed for letting the disease into the country in the first place.

“This was what exactly what was needed,” Jun Nishikawa, a professor of economics at Waseda University who writes about food issues. “You can’t trifle with food safety.”

And Japan’s homegrown mad-cow jitters aren’t over yet.

The most recent confirmed infection was in November and involved a 21-month-old bull. It strengthened the case for those who argue for testing of animals younger than 30 months, and officials say the tighter screening system has done its job — keeping meat from infected animals from finding its way onto dinner plates.

“This is how Japanese beef regained the trust of consumers after the BSE scare here,” the Asahi newspaper said in an editorial last week. “It will not be possible to resume U.S. imports while consumer anxiety lingers.”