WASHINGTON, Jan 23 (Reuters) - U.S. farm and trade officials raised "grave concerns" over Mexico's agricultural biotechnology policies in meetings with their Mexican counterparts on Monday, as lingering disagreements threaten decades of booming corn trade between the neighbors. The United States accounts for most of Mexican corn imports. U.S. officials traveled to Mexico to discuss Mexico's approach to agricultural biotech products. Mexico's agriculture ministry declined to comment, while the country's economy ministry, which handles trade, did not immediately provide comment. Mexican officials have said they will keep importing GM corn for animal feed.

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