On a recent afternoon, across the street from the White House, the Environmental Working Group (EWG) set up an impromptu taste test and asked participants to choose between two oat-based cereals: one that likely contained a pinch of Monsanto's weedkiller linked to cancer, glyphosate, and another that did not.

Given a choice between cereals that likely contained varying levels of glyphosate, and oat-based cereal grown organically without the toxic weedkiller, the steady stream of people who took the taste test all chose the one free of Monsanto's carcinogenic herbicide.

"The response by everyone who participated in the taste test confirms what EWG has been saying for years," said EWG President Ken Cook. "Nobody wants to eat toxic pesticides with their food."

"Unfortunately, it appears executives at big food companies like General Mills and Quaker don't agree, even though it would be an easy fix to produce these cereals without glyphosate," Cook said. "The companies continue to hide behind the federal government's excessively high limits for glyphosate in food, and have not responded to multiple requests from EWG to pursue solutions," Cook added.

Two separate rounds of laboratory tests commissioned last year by EWG found glyphosate — the active ingredient in Monsanto's Roundup weedkiller — in nearly every sample of popular oat-based cereal and other oat-based food marketed to children.

The brands in which glyphosate was detected included several cereals and breakfast bars made by General Mills and Quaker.

How did this weedkiller find its way into popular breakfast cereals marketed to children? Increasingly, glyphosate is sprayed just before harvest on oats, and also on other grains, such as wheat and barley, to kill and dry out the crops so they can be picked earlier from the fields.

230,000 people have signed EWG's petition, urging Quaker and General Mills to source oats that have not been drenched with this toxic herbicide, but so far these companies have ignored the growing calls of concern.

"Consumers have spoken," added Cook. "But Quaker and General Mills clearly don't adhere to the credo that in America, the customer is always right. That's why EWG will expand our testing of these companies' products in 2019, and why we'll be taking our campaign and petition on the road to cities across the country this spring. We need to remind consumers that popular cereals commonly marketed to kids are contaminated with Monsanto's notorious, carcinogenic weedkiller."