Mary Waters heads one of those food groups, the North American Millers' Association. She says even a small amount of the maize could cause problems if it mixes with corn used to make food.

MARY WATERS: "It would only take one kernel in ten thousand to affect food processing."

Snack foods made with corn are a six-billion-dollar industry in the United States.

In two thousand one, genetically modified corn made by Syngenta was found in the food supply chain without approval. Syngenta paid a fine to the government.

Jim McCarthy, president of the Snack Food Association, says the incident caused no health problems.

JIM McCARTHY: "But it did cause major disruptions in the availability of food-grade corn. So we do think this will have a major impact. And we’re urging Syngenta to rethink this."

Syngenta says it will take measures to keep the new maize out of the food supply. Jack Bernens says the company will sell seeds only to farmers who take their crops to nearby ethanol processing plants. He says the company will not sell seed in areas where food makers get their maize.

Mr. Bernens says the company has done a lot of research and found that the risk from a few kernels is overstated. The food industry groups object to conditions placed on companies that want to study that research. Syngenta says it has trade secrets to protect.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson and Steve Baragona . I'm Bob Doughty.