USDA’s Animal and Plant Health Inspection Service says it has been unable to identify the exact mechanism for the introduction of trace amounts of genetically engineered LibertyLink rice into two commercial rice varieties, Cheniere and Clearfield 131.

Officials with APHIS’ Investigative and Enforcement Services and USDA’s Office of the Inspector General said they reached the conclusion after 14 months of investigation into the discovery of the LLRICE601 line in the long grain variety Cheniere.

As a result, APHIS Administrator Cindy Smith told reporters participating in an Oct. 5 press conference the agency will not be pursuing enforcement against Bayer CropScience, the company which developed and field tested the regulated GE rice lines known as LLRICE601 and LLRICE604.

Investigators spent more than 8,500 staff hours, gathered information from 11 states, and visited more than 45 sites in five states and Puerto Rico, said Smith. In addition, USDA officials tested nearly 400 samples from 57 rice varieties harvested between 2002 and 2007.

“We knew at the start of the investigation we faced a difficult task because the field tests for these GE lines were conducted from 1998 to 2001,” she said. “To compound the issue, through the course of the investigation we discovered that some records that might have been pertinent had not been maintained and were not available to investigators.

“Given the lack of available information and evidence, USDA was unable to make any definitive determinations that could have resulted in enforcement action.”

Investigators had hoped to identify how each of the two GE rice lines entered the commercial rice supply after Bayer CropScience reported trace amounts of LLRICE601 were discovered in Cheniere. That investigation, which was launched Aug. 1, 2006, was expanded on Feb. 16 of this year to include trace amounts of LLRICE604 in Clearfield 131.

From 1999 to 2001, LLRICE601 and Cheniere were both grown at the LSU AgCenter’s Rice Research Station in Crowley, La. The Crowley research station was working under a Bayer CropScience contract.

LLRICE604 and CL131 also were grown at the Crowley research station, but the planting of LLRICE604 and CL131 did not occur at the same time. This means that the most likely entry point for LLRICE604 into CL131 was through a means other than direct cross-pollination, Smith said.

Smith said both GE rice lines have the same added protein, commonly referred to as the PAT protein, which has been safely used in other deregulated products for more than 10 years.

As a result of extensive sampling, investigators were able to determine that the presence of LLRICE601 was limited to Cheniere and that the presence of LLRICE604 was limited to CL131. In both cases, only trace amounts of GE material were present. No short- or medium-grain rice varieties tested positive for either LLRICE601 or LLRICE604.

APHIS is releasing a report of the findings as well as lessons learned from this and other investigations and from its experience as regulators. For example, APHIS is considering establishing retention requirements for records. APHIS also is considering greater isolation distances between seed breeding fields and GE varieties in order to reduce the likelihood of pollen flow.

“Based on our findings, we are considering a number of actions to strengthen our enforcement and investigation capabilities and to foster better quality management practices,” said Smith.

USA Rice Federation has been asking USDA officials to release the report’s findings, saying it was needed to help persuade the European Union to reopen its market, which was closed to U.S. rice following the LLRICE601 discovery in Cheniere.

“EU officials have made it clear that current emergency inspection requirements on U.S. long grain rice will not be removed absent the results of USDA’s investigation,” said USA Rice Chairman Al Montna. “These inspection requirements are the single greatest factor preventing a return to normal commercial rice exports to the EU.”

Montna said USA Rice leaders felt vindicated by the APHIS findings. “Given the lack of meaningful explanation by APHIS into what cased the LibertyLink traits to be in the U.S. supply, the push by the rice industry was the right thing to do,” he said. “Imagine if we had waited for APHIS to release its findings.”

Extensive testing of the 2007 rice crop so far has found no further evidence of the LibertyLink traits, USA Rice Federation officials have said. Almost every truckload of rice in the Southern rice growing states is being test for the LL traits.

“Rice farmers have done and are doing everything they can to produce a LibertyLink-free crop,” said USA Rice Producers’ Group Chairman Paul T. Combs. “We have made remarkable progress so far, exceeding expectations for the first year.”

“The ultimate proof of 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 U.S. rice export trade,” Montna said.

“APHIS did a thorough investigation, and we cooperated fully,” said David Boethel, vice chancellor for research at the LSU AgCenter. “I also want to express my appreciation for the professionalism of Steve Linscombe and his staff at the Rice Research Station in cooperating with this investigation.”

APHIS is considering regulatory changes, such as increasing isolation distances between seed-breeding fields and genetically engineered varieties to reduce the likelihood of pollen flow. APHIS personnel said the investigation revealed none of the LLRICE601 line was grown closer than 165 feet of the Cheniere variety.

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