Rust is iron oxide (Fe2O3) so it is produced by exposure to oxygen in air. To protect, you need to prevent air from getting to the hooks/loops.
The easiest way to do this will be to oil them - spray some light lubricating oil onto a cloth/paper towel, rub over all surfaces of the hooks.
I have found that using a mixture of a cap full of bleach with the detergent and adding a cup of pine sol helps. As well as turning your water heater up a small amount. I would also highly recommend using anti fungal powder in between your toes after showering and throughout the day as needed, as a preventative.