Most homes do have mold. It may not be visible, it may not be
growing, but it is there. Unless that Ac is running all the time,
water sits in the pan for some length of time and collects dust and
whatever blows over the coil. Dust, skin, dander, pollen, whatever.

An examination that could be done by any professional person armed with
Petri dishes, swabs, et al, would reveal a very wide range of molds,
bacteria and even disease. Bread molds when someone leaves the bag open for
a short time. Mold is so common, it is unreal, but since it isn't visible,
most people think they live in some bubble somewhere.

The nastiest place in anyone's house is the kitchen sink, followed by
bathrooms. Buy a good UV flashlight, and have a look around in the dark.
It's scary.

Steve