Drive-in restaurant chain Sonic Corp. (SONC) Monday said quarterly earnings rose 25 percent as sales of new products and increased customer traffic helped offset a spike in tomato and beef prices.

Net income for the fiscal first quarter ended Nov. 30 was $16 million, or 26 cents per share, compared with $12.8 million, or 21 cents per share, a year earlier.

Wall Street analysts, on average, had expected the company to report earnings of 25 cents per share, according to Reuters Estimates.

Sales at Sonic restaurants open at least 15 months, or same-store sales, rose 8.1 percent during the quarter.

In the current quarter, Sonic expects to earn about 19 cents a share, up from 16 cents a share in last year's second quarter. Analysts' average estimate is 20 cents a share, according to Reuters Estimates.

Higher franchising income is expected to help offset a rise in commodity and labor costs.

Same-store sales, a key retail measure, are expected to rise at least 2 percent to 4 percent in the period.

Sonic, based in Oklahoma City, operates more than 2,900 drive-in restaurants, mainly in the southern United States.

The company's stock was down 4 cents at $29.60 in after-hours trading on Inet (search) after closing at $29.64 on Nasdaq (search).