Depends on the cheese. Hard cheese can usually be trimmed and saved; soft cheese with mold should be thrown out.
Mold on cheese isn't automatically a discard-it situation — cheese is, after all, made with mold and bacteria to begin with. What matters is how dense and moist the cheese is, since that determines whether mold roots stay on the surface or spread through the whole piece.
The USDA draws the line at texture: firm cheeses give mold nowhere to hide below the surface, while soft, moist cheeses let it travel.
For hard cheeses like cheddar, parmesan, gouda, or Swiss, the USDA says it's fine to cut away at least 1 inch (2.5 cm) around and below the moldy spot. Keep the knife away from the mold itself so you don't drag spores across the rest of the cheese, then re-wrap the cut piece in fresh wrap or a clean container. This works because the dense, low-moisture structure of hard cheese keeps mold roots mostly confined near the surface.
Soft and crumbly cheeses — cream cheese, ricotta, cottage cheese, brie, shredded cheese, and sliced deli cheese — should be discarded entirely if mold appears. Their higher moisture content lets mold roots spread invisibly through the whole product, well beyond the visible spot, and shredded or crumbled cheese has so much surface area exposed that mold can travel through the whole bag.
Blue cheeses like gorgonzola or roquefort are made with intentional mold strains and can be eaten as normal. The concern is unexpected mold on a cheese that isn't supposed to have any — a fuzzy white, green, or black patch on cheddar is a problem; the blue-green veining running through blue cheese is not. Soft-ripened cheeses like brie and camembert are trickier: their white rind is intentional, but any additional fuzzy or colored mold on top of that rind is not and means the wheel should be discarded.
Wrap cheese in wax or parchment paper rather than plastic wrap, which traps moisture, and keep it in the warmer part of the fridge, like a produce or cheese drawer, rather than the coldest zone. Buying cheese in a size you'll actually finish within a couple of weeks also cuts down on how often you're gambling with a half-used block sitting in the back of the fridge.
Firm cheese earns the benefit of the doubt with a good trim; soft cheese doesn't. When texture is uncertain, throwing it out costs less than a foodborne illness.
Yes. Blue cheeses like gorgonzola and roquefort are made with edible mold strains on purpose — different from unexpected mold on a cheese that isn't supposed to have any.
For hard cheese, the USDA recommends cutting at least 1 inch around and below the visible mold, then re-wrapping the rest in fresh packaging.
It can, especially soft cheese, where mold can produce toxins that spread beyond the visible patch. Hard cheese is lower risk because mold usually stays on the surface.
Not necessarily at first. Trust visible mold and texture changes as much as smell, and when in doubt with soft cheese, discard it.