Mexican President Andres Manuel Lopez Obrador announced on Monday that he will sign an agreement this week to ensure that tortillas, one of the country’s signature dishes, will be made only from local non-genetically modified white corn, Reuters reported.

He argued that imposing tariffs on imports of white corn from countries that do not have trade agreements with Mexico would encourage purchases of local corn, without citing possible price increases due to the restrictions.

Mexico, the country where modern corn is grown, is mostly self-sufficient when it comes to white corn, but imports huge amounts of yellow corn, which is used mostly for animal feed.

The country is also in a trade dispute with the United States over a previous decree by Lopez Obrador that imposed restrictions on the use of genetically modified corn, especially for human consumption, with almost all imports coming from American suppliers.

Both the U.S. and Canada have sought advice on mediating the disputes, arguing that the policies pursued by the Mexican government are not based on science and are negatively affecting the North American market as a whole.

If a new round of consultations fails to resolve the conflict within 75 days of the request on June 2, the US can turn to international arbitration by an independent commission.

Mexican president’s dispute with foreign corn

López Obrador, a left-wing populist accused of anti-democratic missteps after being elected president in 2018, has repeatedly said that genetically modified corn will have negative consequences for human health.

On Monday, he assured that the agreement he will sign will guarantee that only traditional white corn will be used to make the traditional tortilla.

He launched a tirade against white corn from South Africa, a country from which Mexico gets a small portion of its needs, accusing it of having “residues” of genetically modified corn.

“We have evidence,” he noted.

Mexico imports about $5 billion worth of corn from the United States annually, the vast majority of which is genetically modified yellow corn, which is used to feed chickens, cows and pigs, and for other industrial purposes.