On the same day that President Barack Obama signed a bill requiring labeling for genetically modified organisms (GMO), a genetically modified wheat field was discovered in Washington State.

The legislation, which was passed by Congress two weeks ago, requires most food packages to carry a text label, a symbol or an electronic code readable by smartphone that tells consumers whether the food contains GMOs.

How the modified wheat cropped up in Washington was not immediately clear, but the US Agriculture Department (USDA) said there is no evidence it has entered the market.

But if it did, the Food and Drug Administration (FDA) said "it is unlikely that the wheat would present any safety concerns if present in the food supply."

A farmer discovered more than 20 plants in a field. The wheat was developed to be resistant to the herbicide known as Roundup, which was created by the seed giant Monsanto, according to the USDA.

An agency spokeswoman did not know where in the state the field was found.

After genetically modified wheat unexpectedly turned up on an Oregon farm in 2013 some Asian countries temporarily banned US wheat imports.

A similar incident occurred in a field at a university research center in Montana in 2014.

The USDA now has two years to write up the rules regarding GMO labeling that will override a Vermont law that went into effect earlier this month.

Sanders slams federal law

Vermont's congressional delegation bitterly opposed the national legislation, saying it was less strict than their law.

Unlike the three labeling options the national law allows, the Vermont law would require items be labeled "produced with genetic engineering."

Critics say many people do not have smart phones, and would not be able to read a code that is to be detected by such a phone.

Vermont Senator Bernie Sanders, whose recent presidential bid fell short to Hillary Clinton, slammed the law coming out of Washington.

"The legislation that passed is an outrage and speaks to the power of big money in American politics," Sanders said.

Indeed, the food industry is pleased with Washington's new law. Among other things, they were eager to avoid a patchwork of rules and regulations put forth by individual states.

While the FDA says GMOs are safe, critics say not enough is known about the risks. They want GMOs labeled so people know what is in their food.

GMOs are plants or animals that have had genes copied from other plants or animals inserted into their DNA.

bik/jlw (AP, dpa)