In a letter to Japan's Food Safety Commission Tuesday, U.S. officials welcomed the recommendation to eliminate blanket testing for bovine spongiform encephalopathy for cattle under 20 months of age but urged that the standard be changed to cattle under 30 months of age, according to the Kyodo News Service .

Despite two preliminary cases of BSE in cattle aged 21 and 23 months discovered recently in Japan, the United States wants the minimum age for testing raised to 30 months. No international authority has confirmed the two findings, the letter said, and the age should be raised to move Japan "toward harmonization with international practice."

There has been no official Japanese response to the letter so far.