There are strict regulations surrounding the sale of dairy products. Your production must comply with state dairy ordinances and licensing, and you must supply the market management with documentation of such compliance.
However, it might not be that hard to get licensed. If you are buying grade A milk you don't have to worry about licensing a dairy just a processing plant. Most likely you will need a kitchen away from you living area and a separate bathroom not for household use, a three compartment sink and a hand wash sink. Check with your state dairy board for more info.