Grocery prices are going up after nearly flat-lining in 2010, say experts who point to short supplies in wheat, cattle and corn as the cause.

Economists for the U.S. Department of Agriculture are forecasting inflation as high as 5.5 percent for some items as world supplies of key food commodities fail to keep up with demand. Economists on Wednesday warned of higher prices for many items as corn reserves hit a 15-year low.

The corn announcement was significant because it's used in many products — Captain Crunch, animal feed, soda sweeteners, ethanol-blended gasoline. Having so little corn in storage — roughly 5 percent of what's expected to be consumed — means the prices could jump quickly if anything goes wrong with the crop.

“I think we have a chance to test the all-time high” price of $7.65 a bushel, Telvent DTN analyst John Sanow said. The tight level of reserves leaves little margin if there are production problems this year, he said.

Major food-makers and some restaurants have already said they'll be raising prices this year because they're paying more for corn, wheat, sugar, coffee and chocolate, all of which are at historically high prices. Weather, including flooding in Australia and droughts elsewhere, has hurt many crops this year.