Portland, OR -

An Oregon milk producer has sued to overturn the state's ban on advertising raw, unpasteurized milk for sale at the farm.

The suit was filed on Tuesday in U.S. District Court in Portland and says the ban violates the free speech rights of Christine Anderson of McMinnville, owner of the Cast Iron Farm.

Oregon prohibits retail sales of raw cow milk but allows on-farm sales if the farmer has fewer than three cows.

Farmers are prohibited from advertising the milk online, in fliers, via email or on signs.

The suit says the ban makes it difficult for Anderson and other farmers to sell their products and prevents consumers from getting truthful information about the milk.

The suit was filed by the Virginia-based Institute for Justice, a public interest law firm.