USDA can't pinpoint how biotech rice taint occurred

WASHINGTON (Reuters) - A lengthy U.S. investigation failed to pinpoint how trace amounts of a biotech rice under development at a research facility made their way into two widely grown varieties of long-grain rice, Agriculture Department officials said on Friday.

The biotech rice and the commercial varieties, Cheniere and Clearfield, were grown from 1999 to 2001 at a research station in Louisiana. They were not intended to be mixed.

U.S. rice exports suffered a serious disruption at harvest time in 2006 when Bayer CropScience reported that trace amounts of its biotech rice were found in Cheniere rice. It was found in Clearfield 131 rice on February 16.

"We were not able to determine the exact mechanism" that introduced the Bayer CropScience biorice material into Clearfield and Cheniere, said Cindy Smith, head of the USDA's Animal and Plant Health Inspection Service.

No enforcement action will be taken against Bayer CropScience, she said.

During a telephone news conference, Smith said APHIS was considering stronger regulations, such as specifying how long researchers must keep records and the kinds of documents that must be kept. APHIS said it also may require greater separation of seed breeding beds and genetically engineered varieties "to reduce the likelihood of pollen flow."

A proposed regulation may be unveiled in spring 2008.

Agriculture Undersecretary Bruce Knight told reporters separately the review found "no smoking guns."

Cheniere and LLRICE601 were grown at the same time at the Rice Research Station in Crowley, Louisiana. Clearfield 131 and LLRICE604, also developed by Bayer CropScience, were grown at the station but not planted at the same time.

Bayer CropScience developed LLRICE601 and LLRICE604 to be herbicide tolerant. LLRICE601 was not approved for commercial use when it was detected in Cheniere rice, but was deregulated in November 2006.

But damage had already been done to U.S. rice exports, which were effectively blocked from Europe.

Direct cross-pollination was ruled out as the most likely entry point for LLRICE604 and Clearfield, Smith said.

Other possible routes include seed-mixing and human error, such as mislabeling of containers.

Because the plantings at the Crowley farm took place several years ago, information is "many years old" and may never have been recorded, said Smith. There were no original field trial maps for the rice varieties, she said, as an example.

Smith said APHIS expected to hold "very specific discussions" with Bayer CropScience and Louisiana State University, which runs the Crowley farm, on how to strengthen field trial procedures.

The trade group USA Rice Federation said tests showed "the overwhelming absence" of the Bayer CropScience biorice in the U.S. rice harvest in the South this year. It pointed to work by the industry to plant untainted seed going forward.

"The ultimate proof the plan's success will be tied to the industry's ability to reopen markets that have been closed to U.S. rice or in which costly restrictions have been imposed on the U.S. rice export trade," said Al Montna, the group's chairman, in a statement.