In California, you go through the Dept of Health I believe. There are certain requirements to be met, and you must be certified to safely handle food.
One of the primary requirements is that you will need to do all of your cooking in a commercial kitchen. You cannot sell food that has been prepared in a residential kitchen.
That's for the state cert. Your city might have different requirements. For my own, Martinez, CA, the Dept. of Weights and Measures handles food safety.. (go figure)