NORTHLAKE, Ill. -- Dominick's Finer Foods here said Robert A. Mariano, president and chief operating officer, has been named chief executive officer. He retains the title of president; a company spokesman said Dominick's will operate without a chief operating officer. Mariano succeeds Ron Burkle, formerly chairman and CEO of Dominick's, who continues as chairman. Burkle is managing partner of Yucaipa Cos., the Los Angeles-based investment firm that acquired Dominick's last February. Burkle, who had also been chairman of Ralphs Grocery Co., Compton, Calif., gave up that post last week. Mariano joined Dominick's in 1973 as a part-time delicatessen clerk. At the time of Yucaipa's acquisition, Mariano was senior vice president of marketing, merchandising and procurement. Burkle said Mariano's appointment to CEO came "in recognition of his outstanding leadership qualities and the continuing success of the company under his management." Dominick's operates 97 stores, including 80 Dominick's and 17 Omni stores.