I haven't started it, but I did some research on it. Basically, a legal home kitchen in MA is called a "residential kitchen." If you're doing retail sales, you will be licensed and inspected by your local board of health. If you're doing wholesale, you will be licensed and inspected by the state.
It does seem to be more doable here in MA than in some other states.
The best way to research on the web is to go to www.massachusetts.gov
then type in "residential kitchen" in the search field. Then go to city hall and they'll probably give you the runaround, but if you're persistant you'll get the info you need.
Hope this helps.