While visible only on the surface of the cheese, molds have hair-like filaments that can reach far into a soft cheese. We once thought that molds were pretty harmless. However, now we know that some molds can form toxins or poisons. These cheeses have a longer shelf life than soft cheeses because of their lower moisture content. They will maintain quality longest if stored in the refrigerator, but they can tolerate longer periods of time at room temperature.
Spoilage generally appears as mold on the cheese.
Because these cheeses are hard, mold filaments are not as likely to penetrate far into the cheese. If a small amount of mold is on the cheese, simply cut off the mold and about one inch of the cheese it covers. When large amounts of mold cover the cheese, it is best to throw it out. Keep these products refrigerated at all times. When mold appears on these products, throw them out.