Top agriculture officials from the United States, Canada and Mexico say they are working together to contain the spread of mad cow disease, but are not yet ready to lift the present ban on U.S. beef trade.

The officials said they are working to update and harmonize safeguards in the entire North American beef industry.

After meeting in Washington on Friday, Mexico's secretary of agriculture said his country will continue a ban on U.S. beef products until the United States implements new industry safeguards. Mexico resumed importing beef from Canada late last year.

U.S. Secretary of Agriculture Ann Veneman told reporters that the U.S. industry has already implemented many new safeguards, but others are taking longer, such as a system that tracks where an an animal was born.

"We have said we would move quickly to work on an animal identification system, but that one is going to take a little more time," she said.

Secretary Veneman went on to say beef trade with Mexico could resume before the identification system is completed.

A U.S. agriculture delegation plans to go to Japan next week to discuss that country's ban on U.S. beef products. Dozens of countries banned U.S. beef products after a dairy animal infected with mad cow disease was found in Washington State last December.

Following an extensive inquiry, the animal was discovered to have been born in Canada, prompting officials to re-examine safety and tracking procedures in the North American beef industry.

Mad cow disease, formally known as bovine spongiform encephalopathy (BSE), is a fatal illness that affects the brain. Humans can contract the disease through eating certain infected beef products.