An unapproved biotech trait was found at “extremely low” levels in some 2006- and 2007-crop U.S. corn, but the grain poses no safety threat and export trade is not likely to be affected, the USDA said on Friday.

The unapproved biotech trait, known as Event 32 (E-32), was found at levels of approximately 3 seeds/1,000 in samples of the Herculex RW and Herculex XTRA Rootworm Protection corn varieties produced by Dow AgroSciences LLC, a subsidiary of Dow Chemical Co.

Dow reported the discovery to the government on Jan. 25, said Cindy Ragin, spokeswoman for USDA's Animal and Plant Health Inspection Service (APHIS).

"We took steps to investigate the information that was submitted to us by Dow," Ragin told Reuters News Service. "We don't think our trading partners will stop corn trade with the U.S. There are no food or feed safety concerns."

In addition, APHIS’ scientific analysis concluded that E-32 poses no plant pest or environmental concerns, according to a release on the agency’s Web site.

The 2008 corn crop will not be affected when it is planted this spring as affected seed that was shipped to farmers for the 2008 planting season has been recalled by Dow.

APHIS said the unapproved biotech trait produces proteins that are identical to an approved trait and are therefore covered by an existing tolerance exemption. The approved trait is also permitted by several foreign countries.

Farmers planted 53,000 acres with the affected seed in 2007, Dow told APHIS.

Given the low levels of E-32 in the Herculex productions and the fact total U.S. corn plantings last year were more than 93 million acres, APHIS calculated that any amount of E-32 in harvested corn would be negligible.

“It is estimated that no more than 0.00002% (two ten-thousandths of one percent) of the 2007 corn crop may have contained E-32,” APHIS said.

In a news release on its Web site, Dow said the GMO contamination originated with a small research plot. The seed was inadvertently sold to farmers by Dow AgroSciences' affiliate Mycogen Seeds.

U.S. grain traders told Reuters News Service the discovery would not affect U.S. corn sales.

"Demand is too strong and alterative suppliers too few," said a grain trader. "But it could make it more difficult if there are new testing and analysis requirements. And it certainly gives us another black eye."

Editor’s note: Richard Brock, The Corn And Soybean Digest's Marketing Editor, is president of Brock Associates, a farm market advisory firm, and publisher of The Brock Report.