From google: Good mold on blue cheese should be a blue-green or gray-blue color and should be evenly distributed throughout the cheese. It should also be moist, but not slimy, and should have a strong, tangy smell. The cheese should be soft and crumbly, and should have a sharp, tangy flavor. However, any time you see black or dark red mold growing on any cheese, throw it away, Png said. It's rare but it can be toxic. dark cheese is bad and also the ones mold is not evenly distributed.