Moldy cheese: Is it unsafe to eat?

December 23, 2007

The answer depends on the type of cheese. Molds are microscopic organisms that have thread-like roots that burrow into the foods they grow on. Most molds are harmless. Molds are even used to make some kinds of cheese, such as Roquefort, Gorgonzola, brie and Camembert. These molds are safe to eat.

But mold on cheese that’s not part of the manufacturing process can also harbor harmful bacteria, such as listeria, brucella, salmonella and E. coli. With hard and semisoft cheese, you can cut away the moldy part and eat the rest of the cheese. But soft cheeses should be discarded.

Moldy cheese? What to do:

Type of cheese/Examples/Handling

Hard Cheddar, Colby, Swiss, Parmesan, Romano, Gruyere Safe to eat if the mold is removed. Cut off at least one inch around and below the mold spot. Keep the knife out of the mold itself so that it doesn’t cross-contaminate other parts of the cheese. Cover the cheese in fresh wrap.

Semisoft American, Asiago, baby Swiss, Monterey Jack, mozzarella, Muenster, Gorgonzola Safe to eat if the mold is removed. Cut off at least one inch around and below the mold spot. Keep the knife out of the mold itself so that it doesn’t cross-contaminate other parts of the cheese. Cover the cheese in fresh wrap.

Soft Brie, blue cheese, Camembert, cottage cheese, Neufchatel, feta, ricotta, shredded and sliced cheeses Discard the cheese.

Source: U.S. Department of Agriculture, 2006

To prevent mold growth on cheese, follow these tips:

Keep cheese and cheese dishes covered with plastic wrap.
Always refrigerate cheese. Don’t allow cheese to sit at room temperature for longer than two hours.

4 Responses to “Moldy cheese: Is it unsafe to eat?”

  1. Morgan Says:

    How do you refrigerate cheese and keep some of them (especially the soft cheeses liek brie and camembert) from takining on the amonia smell that comes of being too cold? are these cheeses perhaps best not to be stored at all?
    I notice that at our cheese mongers and grocersthe fridges are all wide open, and not nearly so cold as the household fridge needs to be to protect milk and butter and root vegetables from spoiling.
    Also, have you any thoughts on long it is safe to keep farm-fresh eggs ourt on the counter. We have a friend who says up to two weeks is fine, but that he comes from a big family so they consume their hen-laid eggs within a day or two all the time. What they cannot consume, we buy from them. I’d like to keep them at room temperature, too; however, wo seeks seems a little long and it can, indeed, take us that long to run through a dozen.

  2. Rise Up Says:

    Hi Morgan,
    I’ll give your egg question a try. Maybe someone else can help you will the cheese questions. Eggs stored at room temp will last about a week. A quick check for freshness is to pop the raw egg in its shell in a bowl of water. If it sinks to a completely horizontal position it’s very fresh; if it tilts up slightly it’s probably around a week old and if it floats it’s probably far from fresh. The most likely reason this test wouldn’t work is if an egg had a weak shell or fine cracks which can also cause the egg to float.

  3. Morgan Says:

    Thanks for the advice about the eggs!

  4. Editor Says:

    Hi Morgan,

    Thanks for the great questions. Here’s some info for you on cheese:

    Purchase only as much cheese at one time as you can eat in 2 or 3 sittings to avoid having to store cheese for too long. Store cheese in the warmer parts of your refrigerator, such as a produce drawer or the top shelf, away from the fan. Always rewrap cheese after it has been opened using a fresh wrapping. Plastic wrap is acceptable for wrapping cheese. Some purists believe that plastic wrap does not allow the cheese to breathe. They will only use wrappings such as waxed paper, parchment paper, butcher paper or aluminum foil. Some feel that plastic wrap imparts a flavor to the cheese, but new improvements in the quality of plastic wrap now make that less likely. If cheese is wrapped in plastic, the wrapping should be changed every few days to allow the cheese to breathe, and to keep the cheese from becoming slimy or discolored. Different types of cheese require different methods of storage. Follow these simple guidelines:
    Hard cheeses with little moisture (such as Parmesan, Dry Jack) should be wrapped to avoid further moisture loss using plastic wrap.
    Semi-hard cheeses (such as Cheddar, Jack, Swiss) can be wrapped in either plastic or waxed paper or parchment paper.
    Semi-soft cheese (such as Brie, Gorgonzola) should be wrapped in parchment or waxed paper, or may be kept in a plastic container
    Soft or fresh cheeses (such as Ricotta, Feta) should be kept in a plastic container.
    Double wrap strong, pungent cheese like Blue Cheese or Limberger to avoid having these aromas permeate the refrigerator. It is best to place these cheeses in an airtight container for extra assurance against aroma leakage.
    If a cheese develops a mold, slice the cheese about ½ below the mold to insure that it has been entirely removed, the rest of the cheese will still be fine. The exception to this rule is soft cheese or semi-soft cheese where the mold can more easily spread. Soft or semi-soft cheeses that develop a mold should be discarded.
    Cheese may be frozen but the texture may become crumbly after it is defrosted, and the flavor is frequently diminished. Frozen cheese is best used for cooking. Goat and sheep milk cheeses tend to hold up better when frozen than cow milk cheeses. Defrost all cheeses slowly in the refrigerator instead of bringing them to room temperature right away. Do not freeze cheese longer than one or two months. Cheese that is already cooked and then frozen, such as cheese in a frozen macaroni and cheese, does not suffer in flavor or texture.

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