Looks like federal and private antitrust regulators have milk on the brain. Dean Foods Co., the nation’s largest dairy processor, is now defending three antitrust lawsuits, the latest one in Wisconsin. While private suits are pending in Tennessee and Vermont brought by dairy farmers, the latest accuser is the federal government.

On Jan. 22, the Department of Justice, along with state attorneys general from Illinois, Michigan and Wisconsin, brought antitrust charges against Dean Foods in federal court in Milwaukee. The suit challenges Dean Foods’ acquisition of two milk processing plants from competitor Foremost Farms, arguing the purchase has undermined competition and left many school districts in the three states with a monopoly milk provider.

Dechert is representing Dean in all three cases. Paul Denis, a partner in the Washington office handling the cases, declined to comment.

But Benjamin Brown of Washington’s Cohen Milstein Sellers & Toll, who is representing plaintiffs in the Vermont litigation, said the latest case should signal a warning to the dairy industry. “Private and public antitrust enforcers are all in agreement that there isn’t true competition in the United States markets for milk,” said Brown, who is pursuing a class action on behalf of a group of dairy farmers against Dean Foods and the Dairy Farmers of America. That lawsuit, filed in October, accuses the entities of monopolizing milk distribution and price fixing in the Northeast.

While the Midwest lawsuit differs, Brown said, it carries a common theme: that Dean Foods “has acquired its market power illegally.”

“At the core of the suits is market power and pricing power that Dean Foods exerts,” Brown said.

Dean Foods also faces a proposed antitrust class action in Tennessee, where Howrey is representing more than 4,000 dairy farmers in two suits filed in the Middle District of Tennessee. The lawsuits, filed in 2007, claim that Dean Foods, the Dairy Farmers of America and National Dairy Holdings, along with a number of alleged co-conspirators, conspired to monopolize the production, marketing and processing of milk in the Southeast.

Dean Foods has denied the allegations of creating an illegal monopoly and price fixing. Responding to the government suit filed in Wisconsin, Dean spokeswoman Marguerite Copel said, “We believe that this is unfounded. We look forward to our court date…It will be very clear that competition is alive and well.”

The Justice Dept.’s lawsuit seeks to force Dean Foods to sell the dairy processing plants it bought from Foremost Farms. “The purpose of the department’s lawsuit is to restore competition so that schools, grocery stores and other retailers in Illinois, Michigan and Wisconsin, will pay lower prices for their milk,” said Christine Varney, assistant attorney general in charge of the Antitrust Division, in a statement.

Meanwhile, professor Peter Carstensen of the University of Wisconsin Law School said the dairy industry “better mind its P’s and Q’s” because there is “a lot of scrutiny.” Carstensen said he alerted the Antitrust Division about Dean Foods’ acquisition from Foremost after reading about it in a local paper. (The April 2009 acquisition did not have to be reported to the government by Dean Foods because the purchase price fell below the minimum reporting threshold.)

“The industry really had better clean up its act, or they are going to lose a fortune,” Carstensen said.

Tresa Baldas can be contacted at tbaldas@alm.com.