My wife has made marm. for a number of years. This year we have a problem. She boiled it up 5 days ago without sugar. Circumstances dictated she was unable to move straight on to adding sugar and boiling to set. Returning to the unsugared mash today we have mould all over it. Our question is:- is it safe to add the sugar, boil it up and jar it up for consumption, or is it toxic?