Cheddar, Parmesan, Swiss, and other hard cheeses behave differently. Their dense texture slows the movement of mold, making localized contamination more likely.
This is why experts often recommend trimming away the affected section rather than immediately discarding the entire block.
5Inspect the Entire Block Carefully
Before deciding what to do, take a close look at the cheese.
Check every side of the block for additional mold growth. A single isolated spot is very different from multiple patches appearing in different locations.
Pay attention to color as well. Mold may appear green, blue, white, gray, or black. While color alone does not always determine risk, widespread discoloration can indicate more extensive contamination.
The smell also matters.
Fresh cheddar should have a characteristic sharp, creamy aroma. If the cheese develops a sour, rancid, ammonia-like, or otherwise unpleasant odor, it may be best to discard it.