In the past six months, the rush to produce more corn-based ethanol has doubled the corn's value, increasing costs for foods that include corn as an ingredient or rely on it as animal feed.  The good news, however, is that the increases may be too small for most consumers to even notice.

The value of other crops -- soybeans, cotton, wheat, rice and vegetable crops -- also will likely climb as farmers switch to corn and cash in on prices as high as $4.08 a bushel; prices hovered around $2.22 at this point last year.

Robert Wisner, an agricultural economist at Iowa State University, said, "We've seen a little of the retail food price impact already," and that consumer prices would slowly rise over the next few years as the ethanol industry more than doubles its capacity.

Last month, the U.S. Department of Agriculture said in January that if corn prices rise by $1 a bushel, grocery shoppers should see the price of pork rise about 3% within a couple of years. Rising corn prices will mean less to the cost of cattle because ranchers rely on hay, rangeland and pasture along with corn, and they can feed animals more of the byproduct of ethanol production, also known as distillers grains.

Pat Westhoff, an agricultural economist at the University of Missouri-Columbia, noted that 6 billion bushels of corn are fed to livestock each year. Even if the price were to increase by $2 per bushel, the $12 billion increase in feed is little compared to what consumers spend shopping.  "It is a lot of money, but compared to the $700 billion Americans spend on food in a year ... you're talking less than a 2 percent" increase if all of the cost was passed on to consumers, he said.

Still, food industry leaders remain concerned about the longterm growth in the ethanol industry, forecast to rise from about 5 billion gallons now to 11 billion gallons when new plants being built are completed.  "Food and beverage manufacturers are seeing a significant increase in prices," said Cal Dooley, president and chief executive of the Food Products Association. "This is playing out across the whole ag sector."