Tell Maseca: Consumers Don’t Want Pesticide-Contaminated GMO Flour!

On October 9, the Organic Consumers Association (OCA) reported that samples of Maseca white and yellow corn flour tested positive for concerning levels of glyphosate, the active ingredient in Monsanto’s Roundup weedkiller.

TAKE ACTION! Tell Maseca: Consumers Don’t Want Pesticide-Contaminated GMO Flour!

bag of Maseca brand corn flour

OCA’s testing, organized through its Mexico-based sister organization, also revealed that the some Maseca flour samples tested as high as 94.15 percent for the presence of genetically modified organisms (GMO). That’s a startling finding, given that Maseca flour GMO crops are not allowed to be grown commercially in Mexico.

Those findings can mean only one thing—Mexico-based Gruma, which owns the Maseca brand, is importing GMO corn from the U.S. to produce its flour, sold all over the world, including in Mexico and the U.S.

Maseca is the world leader in corn flour and tortilla production in countries like U.S., Mexico, Central America, Venezuela and Europe. On the Gruma website, the company claims that the Maseca brand is positioned as a “synonym for  quality” and that it is made from “100% natural corn,” and that Maseca brand tortillas are “a natural, healthy and nutritious food.”

If you don’t think glyphosate-contaminated GMO corn is “natural, healthy and nutritious,” please sign this petition.

TAKE ACTION! Tell Maseca: Consumers Don’t Want Pesticide-Contaminated GMO Flour!

Sign the Petition


To: Juan Antonio González Moreno, Chief Executive Officer of Gruma, S.A.B. de C.V. and Grupo Industrial Maseca, SAB de CV.

Dear Mr. Moreno,

I can no longer buy Maseca corn flour or tortillas, until Maseca stops using GMO corn and begins transitioning to 100% organic corn for all of its products.

I was shocked to learn that Maseca flour is contaminated with glyphosate, the active ingredient in Monsanto’s Roundup weedkiller, and that the flour tested as high as 94.15% for the content of genetically modified organisms.

In March 2015, the World Health Organization classified glyphosate as a “probable” human carcinogen. Many studies link glyphosate to numerous illnesses, including cancer and liver and kidney disease. Studies also show that glyphosate disrupts the gut microbiome, which is critical for immune system and digestive health.

In August, a jury in San Francisco, after hearing evidence of how Monsanto covered up internal studies linking glyphosate to non-Hodgkin lymphoma (NHL), awarded Dewayne Johnson $289 million in compensatory and punitive damages. Johnson, a former school groundskeeper who routinely sprayed glyphosate on school properties, is terminally ill with NHL.

On your website, you claim that your corn flour and tortillas are “natural,” “healthy,” and “nutritious.” I no longer believe those claims, and can no longer buy your products until you stop using GMO corn and begin transitioning to 100% organic corn for all of you products.

Thank you