Can mold grow on liquid

Answer 1

Of course. Pour milk into a shallow dish and leave it at room temperature (no sun) for a few days. Voila!: floating mold. It sure can. There have been several times I have left some juice or soda in a cup sitting around and come back to find it several weeks later and there is mould floating on the surface! (I tend to forget about and leave drinks outside in my horse barn while I'm working)