On which food does mold grow best on?

There are different types of mold, and some grow better than others on certain foods. It sounds like a good project. Most likely the mold spores will be found in the air for the exposure of your selected mediums. Fruit spoils by mold growth. Try several varieties of fruit. If you find a piece that has already started to rot, you have the mold already. Vegetables grow mold also. Inside a cut jack-o-lantern mold will grow after about a week. When looking for the fruit try to avoid those which have been waxed to preserve them. Shabirah.