A study conducted by Washington State University found no evidence of further GMO wheat after it was discovered on one farm this spring. The study involved checking over 20,000 plots. Last month, US Animal and Plant Health Inspection Service conducted grain tests and interviews with farmers and found no evidence of further GMO wheat in use.

Monsanto developed the glysophate-resistant wheat over a decade ago, and was tested in fields between 1998 and 2005 before the application was withdrawn from USDA's regulatory approval process. USDA says GMO wheat would be safe if consumed, but a growing number of US consumers are joining those in Asia and Europe who refuse to eat GMO foods.