http://www.ft.com/cms/s/0/249211fc-ec1d-11df-9e11-00144feab49a.html#axzz14t9RPg4J

When somebody says corn is causing the rise in the price of food it's time to look them in the eye and say there is no corn in diet pop but it costs the same as regular pop.  So the rise in prices of many food items has nothing to do with the price of grain.  Indeed grain is the lowest cost part of any food item.  

Shipping, packaging, advertising and distribution (stores) are the major cost items of any food product.

from http://www.ers.usda.gov/AmberWaves/February08/Features/CornPrices.h...

"For example, an 18-ounce box of corn flakes contains about 12.9 ounces of milled field corn. When field corn is priced at $2.28 per bushel (the 20-year average), the actual value of corn represented in the box of corn flakes is about 3.3 cents (1 bushel = 56 pounds). (The remainder is packaging, processing, advertising, transportation, and other costs.) At $3.40 per bushel, the average price in 2007, the value is about 4.9 cents. The 49-percent increase in corn prices would be expected to raise the price of a box of corn flakes by about 1.6 cents, or 0.5 percent, assuming no other cost increases.
In 1985, Coca-Cola shifted from sugar to corn syrup in most of its U.S.-produced soda, and many other beverage makers followed suit (see “High-Fructose Corn Syrup Usage May Be Leveling Off” in this issue). Currently, about 4.1 percent of U.S.-produced corn is made into high-fructose corn syrup. A 2-liter bottle of soda contains about 15 ounces of corn in the form of high-fructose corn syrup. At $3.40 per bushel, the actual value of corn represented is 5.7 cents, compared with 3.8 cents when corn is priced at $2.28 per bushel. Assuming no other cost increases, the higher corn price in 2007 would be expected to raise soda prices by 1.9 cents per 2-liter bottle, or 1 percent. These are notable changes in terms of price measurement and inflation, but relatively minor changes in the average household food budget."