It's very difficult. Although you can't blame the "powers that be" when even commercial producers are coming under fire for poisoning people.
Even back in the 1980's we had (in LI, NY) a local guy who used to raise & butcher his own free-range chickens & rabbits, & sold eggs & homemade cheeses. We bought from him all the time & loved his stuff. Unfortunately, the health department closed him down because, as mentioned above, he didn't have a "commercial kitchen" to work from.
Fast-forward to today & the regulations are stricter than ever. Even at the farmers' markets there are regulations - even as far as just selling eggs. There's even been an ongoing argument about farmers' markets selling prewashed bagged salad mixes - whether or not these should be considered "processed". Apparently anything not "directly from the ground" is considered "processed" here in Virginia.
I would imagine anything like a bottled sauce or salad dressing would be heavily regulated due to the processing factor. Let's face it - one wrong move & a customer could end up a botulism victim.
If you're really interested in pursuing this, I'd contact my local Cooperative Extension office, Health Department, etc., etc.