Fast-food chain operator Jack in the Box posted an adjusted quarterly profit that beat Wall Street estimates as price increases and lower commodity costs helped offset a drop in sales.

For the third quarter ended July 5, Jack in the Box, which operates under its namesake and Qdoba Mexican Grill brands, earned $32.9 million, or 57 cents a share, from continuing operations, compared with $29.5 million, or 50 cents a share, last year.

According to Reuters Estimates, the company earned 60 cents a share, excluding items, topping analysts' consensus view of 58 cents.

Revenue fell 3 percent to $575.7 million, missing analysts' estimate of $587 million.

Looking ahead, the company sees earnings of $2.11 to $2.18 a share from continuing operations for fiscal 2009. Analysts were expecting $2.12.

Shares of the San Diego-based company fell 3 percent to $20.51 in trading after the bell. They closed at $21.16 Tuesday on Nasdaq.

(Reporting by Renju Jose in Bangalore; Editing by Deepak Kannan)