MINNEAPOLIS — Miller Milling has completed its acquisition of a total of four flour mills from two different sellers in a transaction valued at about $215 million.

With the completion of the transaction, Miller Milling, part of Japan’s Nisshin Seifun Group, is set to become the fourth largest milling company in the United States.

“The transaction increases the company’s overall milling capacity, expands its geographic coverage and diversifies its product offerings,” Miller Milling said.

Included in the transaction are mills in Oakland, Calif.; Saginaw, Texas; and New Prague, Minn., acquired from ConAgra Mills, and a mill in Los Angeles acquired from Cargill. The mills have a combined daily milling capacity of 58,600 cwts.

The sale of the four flour mills by Cargill and ConAgra allows those companies, together with CHS Inc., to combine their remaining milling operations into a new company to be named Ardent Mills. The divestiture was required as part of a consent agreement with the U.S. Department of Justice.

Established by John Miller in 1985 as a durum milling company, Miller Milling broadened its flour portfolio in 1998 with the addition of hard wheat milling capacity.

In addition to the mills acquired from ConAgra and Cargill, Miller Milling operates flour mills in Fresno, Calif.; and Winchester, Va. The two mills have a combined daily milling capacity of 36,000 cwts. In 2012, Miller Milling was acquired by Nisshin, Japan’s largest flour milling company. Nisshin was established in 1900 as the Tatebayashi Flour Milling Co. and was renamed Nisshin in 1908. The company grew over time through the addition of new capacity as well as mergers and acquisitions. The company also diversified into processed food, compound feed, pet food, pharmaceuticals and engineering.

Beginning in the 1980s, Nisshin has expanded outside of Japan through joint ventures, start-ups and acquisitions in Thailand, China, the United States, Canada, India, Indonesia, New Zealand and Vietnam.