When moisture is not dried out properly mold will grow. In places of high humidity, and condensation it is especially important to ensure that they are dried properly. As was the case with this shower area. The mold was caused because the moisture levels were very high in this bathroom, and to compound to the issue, there was no vent in the bathroom to remove the condensation.
The best way to deal with mold is to prevent it from growing in the first place. Mold can grow only when moisture can’t get out, and if your bathroom doesn’t have a vent, or if your vent isn’t working properly, that’s the first thing you need to fix. If you do have a vent in your bathroom, make sure that you turn on the exhaust fan during and after your shower. The exhaust fan pulls the moisture out and incidentally, any unpleasant odors as well.