Ethanol does NOT drive up food costs.
Field corn (the product used to make ethanol) is not consumed directly by people. Field corn is used in making a wide variety of products (just as oil is used to make tires, plastics etc, corn is used to make bio degradable plastics and a wide variety of products). So demand has increased the price of field corn at the farm, but the demand was going to go up do to the large number of non-food chain uses of corn. And the by product (used corn) from the ethanol plants goes back into the livestock food production chain as a higher quality product for the livestock than it was before it went into the plant. If anything it might have made food costs lower.