Washington ? Former Sen. Nancy Kassebaum Baker, wife of the U.S. ambassador to Japan, is asking the Agriculture Department to reconsider its refusal to let American meatpackers do their own tests for mad cow disease.

Such testing could promote confidence in U.S. beef and help re-establish exports to countries that ban it now, Baker said in a letter to Agriculture Secretary Ann Veneman.

“At this time in our critical export markets we need to get behind all the best marketing tools we can,” said Baker, wife of Ambassador Howard Baker. He, too, is a former senator.

Japan is one of more than 50 countries with beef import bans in effect. But Baker said she was not writing as a representative of the U.S. Embassy in Tokyo or in any other official capacity. The Kansas Republican said she was stating her opinion as a private cow-calf producer.

Baker noted that the department had rejected a proposal by a small meatpacker, Creekstone Farms Premium Beef, to let the company test cattle slaughtered at its plant in Kansas.

“I’ve come to strongly believe that the time has come for USDA to reconsider the decision made to reject 100 percent testing by meatpackers such as Creekstone Farms,” she wrote.

The letter was released Thursday by Creekstone Farms. Its contents were confirmed by Baker’s son, Kansas State Rep. Bill Kassebaum, R-Burdick. Agriculture Department spokesman Ed Loyd said the department had not yet received the letter.

Creekstone Farms has said Japanese buyers were willing to accept its beef if the company tested every animal and had Agriculture Department certification.

The department rejected the license, and said there was no scientific reason to test every animal. It also controls the rigthts to do the tests.

Although she said she was writing as a private citizen, her status as a former senator and the wife of a high-ranking U.S. official lent prominence to her comments.

It is hard to tell how the letter would affect the talks, said Lynn Heinze, a spokesman for the U.S. Meat Export Federation, a trade group.

The Agriculture Department would consider Baker’s comments spokesman Loyd said. “We always welcome comment and input from our constituencies,” he said.