From 1980 to 1987, Mr. Tanner worked as a Project Engineer with the Ralston Purina Company. In 1985, Mr. Tanner began investing in real estate with Bob Kaminski. Borrowing $26 million together, they purchased the Reddy Ice Group from the Southern Corporation and started to consolidate ice companies. In 1993, Mr. Tanner and Mr. Kaminski bought Suiza Dairy in Puerto Rico to consolidate the dairy industry as they had the ice industry. Mr. Tanner became CEO of Suiza Dairy and the company went public in 1996.
In 2001, Suiza Dairy bought Dean Foods and changed its name to the Dean Foods Company. In addition to being CEO, Mr. Tanner became the Chairman of Dean Foods in 2002. Since November 2007, he served as an Executive Vice President of Dean Foods Co. From November 2007, he served as the Chief Supply Chain Officer of Dean Foods and from January 2012, he served as the President of Fresh Dairy Direct for the company. In 2012, Tanner became Chairman of Whitewave, as well, a spinoff of Dean Foods.
Dean Foods is an American food and beverage company that specializes in dairy products. The company maintains plants and distributors in the United States and the United Kingdom. Dean Foods has 100 facilities located in 35 American states as well as five manufacturing plants in the countries of Belgium, France, the United Kingdom, and the Netherlands.