Microbiological tests required for Scottish candy tablet

Hi all

My name is Ilias. Recently I was asked by a Scottish catering business to help them optimize one of their products which is the tablet. Tablet is a kind of candy that it is made by sugar, condensed milk, semi skimmed milk and butter. This business has already a HACCP plan that follows the EatSafe guidelines. All the ingredients they use come into packaging from retailers. I have detected some problems with the packaging material since it is common greaseproof paper that they buy from a local store. Also I would like to run a check on the final product from a microbiological aspect and the only thing I can think of is check for yeast contamination. Since the final product is of low water activity I don't see any need to check for pathogens.
I would appreciate some info on the final checks, if someone has a better insight in the candy manufacturing.

Regards

Ilias