Dean Foods has denied claims that it operates anti-competitive policies after a US senator launched a scathing attack on the company.

The US Senator for Vermont, Bernard Sanders, has asked the US Department of Justice to investigate possible antitrust violations by Dean Foods.

Sanders claimed that consolidation of the US liquid milk market has depressed dairy prices. 

Responding to these allegations, a spokesperson for Dean Foods told just-food that the company would "take issue" with some of Sanders' "assumptions".

As Dean Foods is "dependant" on dairy farmers to supply raw milk, it is in the company's interests that the farmers businesses are "healthy over the long term", Marguerite Copel, Dean Foods' vice president for corporate communications, said. 

Moreover, Copel contended that dairy prices are generally set by the US Department of Agriculture.

The current low price for fluid milk is the result of over-supply, Copel added. 

"At Dean Foods, we work hard to create demand for our products, which in turn creates additional demand for milk and additional markets for farmers," she concluded.

Dean Foods declined to comment specifically on the competitive nature of the dairy market in Vermont, where the group accounts for 70% of total fluid milk sales.