How to tell the difference between sugar crystals and mold in dried fruit? I am making dried pears and I noticed that there are some white lumps on the surface of the fruit:



This resource says that this phenomenon may occur in figs and that it is sugar crystallizing. However, pears are much less sugary than figs and therefore I am not sure whether this is the same phenomenon.

There is no bad smell and they still taste good. Is there some method that I can use to test whether this is indeed sugar?

The pears were pre-dried in hot-vent oven, then placed into a dedicated fruit dryer for a couple of hours, then placed on a clean sheet of paper on the radiator.
If you are talking about the cut surface of the pears, especially near the core cut-out, those little white dots may be not sugar, but a normal occurrence in pears, little gritty cells in the fruit. They are what crunch between your teeth when you eat a pear, aren't harmful, and are not mold. Mold would be in irregular patches likely with a greenish/bluish/grayish tint, and the larger patches would probably look a little furry, or at least have a matte finish, not shiny. This very uniform array of tiny dots (at least what I see) don't look like mold.