Here in WA, I need to be licensed by the state and then only to sell wholesale. If I want to sell retail I need a food handler permit from the county, though there are temp ones available for farmer's markets.
I think the biggest obstacle, especially while wanting to keep it small, is producing the cheese in a licensed kitchen. I'm lucky in that WA doesn't require a *commercial* kitchen but it does have to be a separate facility than your main household kitchen. I'm actually doing some costing right now to see what it would take to build a small operation, maybe 50 gallons per day, as a part of a greater farm that produces other food items as well, including microbrewed beer (future plans for the family property). The nice thing is that I wouldn't have to buy commercial appliances like fridges, freezers, etc. But still will be pricey because it will have to be a separate facility than my home kitchen.
So I think it really varies by state because I know some states will approve someone's home kitchen, but then others require the food to be made in a commercial kitchen which drives the small guys out of the market. No one can afford to invest $50k to build a commercial kitchen just so sell a bit of cheese! So yeah, check into state and county regulations for food processing cuz everyone's different. I wish I could make cheese at home and sell it!