PARSIPPANY, N.J. — Lower interest expense, lower debt levels and previous refinancing activities contributed to a 160% increase in income at Pinnacle Foods, Inc. during the first quarter.

For the quarter ended March 31, the company has earnings of $24,796,000, equal to 31c per share on the common stock, which compared with $9,539,000, or 12c per share, during the same quarter of the previous year. Sales for the quarter were $612,981,000, down narrowly from $616,925,000.

“We are pleased with our excellent start to the year,” said Bob Gamgort, chief executive officer. “The significant growth in our earnings reflects the strength of our business model and provides us with the flexibility to invest in our business and respond, as needed, to potential heightened promotional activity.”

The company said EBIT for the Birds Eye Frozen segment increased 31% to $48.9 million, which compared with $37.2 million during the same quarter of the previous year. Sales for the segment were up 1% to $292.5 million, which compared with $290.5 million during the same quarter of the previous year.

The Duncan Hines Grocery segment had EBIT of $29.4 million, up 12% from $26.3 million during the same quarter of the previous year. Sales for the segment were up 2% to $227.2 million, which compared with $222 million during the same quarter of the previous year.

The company recently completed the initial public offering of its common stock and began trading on the New York Stock Exchange. The proceeds from the I.P.O. were used to pay down debt, and the company has refinanced outstanding debt.