Re: which cheese will grow mold the fastest is it based on fat, water or protein content?

Generally the rate of mold growth in or on cheese is regulated by available moisture. High moisture cheeses, such as mozzarella, will generally allow faster mold growth than cheeses with lower moisture, such as cheddar. An extreme example of low moisture cheese would be parmesan.

The amount of acidity in the cheese (pH) generally selects for mold growth in place of bacterial growth. While some bacteria can grow at lower pH's (higher acidity), the combination of low moisture and low pH generally restricts the growth to molds.