Kansas City, Mo ? Interstate Bakeries Corp., the maker of Wonder bread and Twinkies, plans to close an unspecified number of plants and jobs during the next three years in an effort to reduce costs after reporting a 59 percent drop in first-quarter earnings.

“We have to automate and we will. We have to rationalize production,” James R. Elsesser, chief executive officer said Friday. “We have too much excess capacity and we have a plan to fix that over time.”

Although company spokes-man Mark Dirkes would not say how many plants would be closed, he said “it will not happen in one fell swoop.”

Interstate Bakeries has 58 bakery plants and 34,000 employees.

The nation’s largest wholesale baker said it earned $11.2 million, or 25 cents a share, for the quarter that ended Aug. 23, down from $27.13 million, or 60 cents a share, a year ago. Analysts surveyed by First Call expected earnings of 23 cents per share.

Sales slipped to $831 million from $839 million a year earlier.