Our Environmental Health department do a one day Elementary Food Hygiene Certificate course, accredited by the Royal Environmental Health Institute of Scotland. It is very basic and there is a short multiple choice exam at the end. The exam / Certificate is not an end in itself but most foor producers and caterers use it as an example of due diligence. Of course, if you don't practice what you learn on the course, the Certificate won't stop you giving somene food poisoning or protect you from prosecution.
Trading Standards will advise on packaging and labelling.
Environmental Health will probably want to inspect the premises - you will have to register with them as a food business. Jam's not a high risk food but you will have to demonstrate that the food will be clean and free from contamination.
Most EHOs and Trading Standards officers are helpful and, while ensuring that the public is protected, are aware of the need to support small businesses.