The US Government's ethanol drive may have boosted the fortunes of corn farmers.
About 1500 activists, led by radical French farmer Jose Bove, have ripped up a field of transgenic corn in south-west France.
The women making blue corn tostadas knead the dough before flattening it, their palms bright blue.
More than 240 kilograms of corn — enough to feed one person for a year — is required to produce 100 litres of ethanol.
With the cost of corn already pushing up food prices, a spokesman for the Grocery Manufacturers Association called the projection alarming.