Be careful of this. There are scam artists who work in collusion with doctors. They take a sample, then complain that you poisoned them or triggered an allergy. Their doctor will verify that fact , and they will sue you for millions. Likely they have a lawyer in on the game as well.Make sure you have coverage for at least a million dollars before doing something like that.99.99% of people will be OK, just beware of the few that are looking to clean you out.
No doubt you already have a permit to sell items similar to a peddlars licence in the UK. I think the only other consideration is to have a food hygeine certificate and public liability insurance (in case someone drops dead after eating something that did not agree with them) But I m in UK where things are probably quite different.