WASHINGTON, D.C., U.S. — The U.S. Department of Agriculture (USDA) said information collected so far indicates the discovery of bioengineered wheat growing in an Oregon field in late May appeared to be a “single isolated incident.” 

“As of today, USDA has neither found nor been informed of anything that would indicate that this incident amounts to more than a single isolated incident in a single field on a single farm,” the USDA said. “All information collected so far shows no indication of the presence of genetically engineered wheat in commerce.” 

The USDA began its investigation on May 3 when an Oregon State University scientist notified the USDA that plant samples had tested positive for a protein that made them resistant to glyphosate, the department said. The USDA said investigators were conducting a “thorough review,” including interviews of the person who harvested wheat from the field, the seed supplier and about 200 area growers. Wheat samples of the producer’s wheat harvests, including wheat from the 2012 harvest, have tested negative for the presence of bioengineered material. 

In addition, the USDA said it had validated an event-specific, DNA-based method for detecting MON71800 (provided by Monsanto to USDA on May 23) that included a specificity study and a sensitivity study. The USDA said it had provided the test method to trading partners who have requested it. 

“USDA determined that the method can reliably detect MON71800 when it is present at a frequency of 1 in 200 kernels,” the department said. 

The department announced May 29 the discovery of a small number of volunteer wheat plants in an Oregon field had tested positive for genetically engineered glyphosphate-resistant wheat, and extensive testing confirmed it was variety MON71800 developed by Monsanto. 

“The detection of this wheat variety does not pose a public health or food safety concern,” the USDA said. 

Monsanto and the Food and Drug Administration completed a voluntary food and feed safety consultation in 2004, which means the wheat variety is as safe as non-bioengineered wheat. 

Japan, South Korea and Taiwan postponed imports of U.S. white wheat after the discovery in May and continue to study information from U.S. officials to determine what, if any future action may be required, the USDA said.