Japan will maintain its stance on restricting some U.S. beef when officials from the two countries hold talks next week, the agriculture ministry said Friday.

Officials from the agriculture and health ministries will meet their U.S. counterparts Tuesday and Wednesday in San Francisco to exchange opinions on U.S. beef, the two ministries said in a joint statement. Japan doesn't allow imports of U.S. beef from animals older than 20 months out of fear of mad cow disease.

"Our stance is unchanged," agriculture minister Masahiko Yamada was cited as saying earlier Friday by ministry spokesman Kenji Nakagawa. "We would like to hold talks based on scientific knowledge as we consider food safety as a very important issue."

U.S. Agriculture Secretary Tom Vilsack agreed with then farm minister Hirotaka Akamatsu to resume bilateral talks on normalizing beef trade, stalled since August 2007, when he visited Tokyo in April.

Companies including Tyson Foods Inc. and Cargill Inc. are losing sales of about $1 billion a year because of Japan's refusal to allow imports of beef from older animals, according to the National Cattlemen's Beef Association.

The World Organization for Animal Health, or OIE, voted in May 2007 to give the U.S. its "controlled-risk" rating for mad cow disease, indicating controls are effective and meat from U.S. cattle of any age can be safely traded. The OIE standards are used to settle trade disputes at the World Trade Organization.