Why is my cheese turning black?
William Burgess
Updated on April 02, 2026
Why is my cheese turning black?
A recently discovered visual defect in cheese has caused some concern within the cheese manufacturing industry. Although not apparent until some degree of cheese aging has transpired, this defect, heretofore referred to as black spot defect (BSD), can result in a dramatic reduction in the value of affected cheeses.
Is black mold on cheese dangerous?
Mold generally can’t penetrate far into hard and semisoft cheeses, such as cheddar, colby, Parmesan and Swiss. So you can cut away the moldy part and eat the rest of the cheese. Cut off at least 1 inch (2.5 centimeters) around and below the moldy spot. These molds are safe for healthy adults to eat.
Is cheese mold dangerous?
Still, it’s important to know which types to eat, as moldy cheese can still be dangerous. Blue and soft-ripened cheeses are grown with specific molds and safe to eat. However, if mold appears on soft, shredded, sliced, or crumbled varieties, you should discard them immediately.
How can you tell if blue cheese is safe to eat?
Fuzzy gray or black patches of mold or shiny pink or yellow spots of yeast are indications that your blue cheese is past the point of no return. Cheese that is slimy or feels tough and dry has also likely spoiled. As with most foods, the easiest way to tell if blue cheese is safe to eat is to use your senses and basic judgment.
Why is my blue cheese turning pink and brown?
If you notice that it’s started to turn pink, brown, or green, your blue cheese has likely spoiled. Just as with the scent of the cheese, make sure to note the color of your blue cheese when it’s fresh so it’s easier to spot changes if it goes bad.
What’s the best way to tell if cheese has gone bad?
A smart thing to do is to smell your cheese when you first purchase it, so you have a good understanding of how it is supposed to smell and you will be able to notice when something is off. Sometimes cheeses can be pungent and “off” smelling to begin with.
What makes American cheese different from other cheeses?
Because its manufacturing process differs from “unprocessed” traditional cheeses, federal laws mandate that it be labeled as “processed American cheese” if made from combining more than one cheese, or “processed American cheese food” if dairy ingredients such as cream, milk, skim milk, buttermilk, cheese whey, or albumin from cheese whey are added.
Fuzzy gray or black patches of mold or shiny pink or yellow spots of yeast are indications that your blue cheese is past the point of no return. Cheese that is slimy or feels tough and dry has also likely spoiled. As with most foods, the easiest way to tell if blue cheese is safe to eat is to use your senses and basic judgment.
If you notice that it’s started to turn pink, brown, or green, your blue cheese has likely spoiled. Just as with the scent of the cheese, make sure to note the color of your blue cheese when it’s fresh so it’s easier to spot changes if it goes bad.
What does mold look like on blue cheese?
But there are some living things you never want to see growing on your cheese, even if mold is the main selling point. Fuzzy gray or black patches of mold or shiny pink or yellow spots of yeast are indications that your blue cheese is past the point of no return.
Why are some cheeses banned in the United States?
Most of the banned cheeses are illegal in the U.S. due to the use of unpasteurized milk, or raw milk, in their production. The FDA deems these milks a public health concern. Foodborne pathogens can grow and spread; pasteurization is meant to kill off these germs. There are some cheeses banned for other health reasons, too.