US federal authorities are investigating allegations that Dairy Farmers of America, the country’s largest co-operative, has manipulated milk and cheese prices.

The co-operative faces antitrust lawsuits by farmers and retailers for allegedly conspiring to suppress prices it paid for raw milk, while raising prices to retailers.
Cheese prices at the exchange affect milk futures and are a key component of a US Department of Agriculture formula to set the minimum prices that dairy farmers receive for raw milk. Consumer milk prices have risen about 32% since the start of 2004, compared with a 15% increase for food prices in general.