Grain shortages, Middle East turmoil and extreme weather in critical crop-producing regions have combined to send retail food prices higher this year, said a Purdue University agricultural economist. Prices could climb further if commodities markets continue their upward march.

American consumers can expect to spend about 4 percent more for food this year than in 2010, said Corinne Alexander. Beef, pork and poultry products likely will see even greater price hikes, she said.

U.S. food price inflation reached 7.5 percent in September 2008 before falling 10.5 percent by November 2009. It's been moving back up ever since.

"We're returning to a period of food price inflation after coming off a period where we saw food price deflation," Alexander said. "We don't expect this to be a long-term, permanent higher food price period. We'll see these higher food prices until we rebuild global stocks of the primary crops."

Shortages in corn, soybean and wheat stocks have pushed prices to their highest levels this decade. Corn and soybeans are used for food products, animal feed and in biofuels production, while wheat is the principal ingredient in breads and cereals.

Since mid-2010, corn futures prices have more than doubled to more than $7 per bushel and could exceed the $7.65 record set in 2008. Soybean prices are up 40 percent from one year ago, to just over $13 a bushel. Wheat futures have risen more than 50 percent since this past July, to $7.75 per bushel.

"With higher grain costs, the biggest food inflation price impacts we expect to see are in the livestock area," Alexander said. "Because those feed costs are up, we're expecting beef prices to be up on the order of 5.5 to 6.5 percent in the coming year. Pork prices will be up on the order of 7 to 8 percent. Poultry prices will rise more moderately because it doesn't take near as much grain to get a pound of chicken as it does a pound of pork or beef, so chicken prices will be up about 3 to 4 percent."