ConAgra Foods Inc reported lower-than-expected quarterly earnings on Tuesday, hurt by higher costs for flour, and said it saw commodity costs for the year rising more than previously expected.

The maker of Hunt's ketchup, Chef Boyardee pasta and Pam cooking spray earned $85.3 million, or 20 cents per share, in the first quarter ended on August 28, compared with $146.4 million, or 33 cents per share, a year earlier.

Excluding one-time items, ConAgra earned 29 cents per share. Analysts on average forecast 31 cents, according to Thomson Reuters I/B/E/S.

Shares of ConAgra were down 2.9 percent at $22.71 in premarket trading.

Sales rose 9.5 percent to $3.07 billion, helped by price increases. Analysts had forecast $2.94 billion.

The results come a day after ConAgra walked away from its months-long pursuit of Ralcorp Holdings Inc after being repeatedly spurned by the maker of Post cereals and private-label foods.

ConAgra said in June that profit growth for the current fiscal year would be below its long-term goal of 6 percent to 8 percent, due mostly to higher costs for everything from meat to packaging.

It warned at the time that first-quarter profit would be lower than a year earlier as price increases have not kept pace with accelerating inflation.

On Tuesday, the company said it expected commodity costs to rise 9 percent to 10 percent in its consumer foods segment, up from its previous forecast of a 7 percent to 8 percent increase.

The company still expects full-year earnings per share to increase at a low to mid single-digit percentage rate from the $1.75 reported for fiscal 2011, excluding one-time items, with the growth coming in the second half of the year.

(Reporting by Brad Dorfman in Chicago. Additional reporting by Martinne Geller in New York; Editing by Maureen Bavdek and Lisa Von Ahn)