Its statement added: “All information collected so far shows no indication of the presence of GE wheat in commerce.”
USDA began an investigation last month after it emerged that some wheat in an Oregon field had tested positive for a variety of biotech wheat* developed by Monsanto (MON71800) several years ago that was never brought to market.
All of these samples of seed and grain tested negative for the presence of GE material
Investigators have now interviewed the person that harvested the wheat from the field in question along with the seed supplier, said USDA , which stressed that “this wheat variety does not pose a public health or food safety concern” and is “as safe as non-GE wheat currently on the market”.
Investigators have also obtained samples of the seed sold to the producer and other grower, plus samples of the producer’s wheat harvests, said USDA, which is now conducting interviews with 200 other growers in the region.
“All of these samples of seed and grain tested negative for the presence of GE material.”
Validated testing can reliably detect MON71800 when it is present at a frequency of 1 in 200 kernels
On June 13, USDA validated a DNA testing method for detecting MON71800 that it is now providing to trading partners upon request, said the statement.
To validate the test - provided by Monsanto to USDA last month - USDA conducted a specificity study and a sensitivity study, which “determined that the method can reliably detect MON71800 when it is present at a frequency of 1 in 200 kernels.
“USDA officials will continue to provide information as quickly as possible as the investigation continues – with a top priority on giving our trading partners the tools they need to ensure science-based trade decisions.”
Legal fall-out
While the incident appears to be an isolated one, it has already prompted a temporary block on imports of US white wheat from Japan, Korea and Taiwan and a string of lawsuits against Monsanto from US farmers alleging that the market uncertainty it has created has depressed wheat prices and damaged export markets.
*The wheat in question was genetically modified to be resistant to the herbicide glyphosate (RoundUp).