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Is Blue Cheese Safe to Eat?

Blue cheese is a moldy cheese made of cow’s, sheep’s, or goat’s milk and aged with cultures of the mold Penicillium, a genus of fungi that are naturally found in nature and generally responsible for food spoilage.

If you’ve ever wondered why blue cheese is safe to eat—yet other moldy foods aren’t— you’re in the right place. I’ve been a fan of blue cheese ever since I tasted my first bite of Roquefort that my dad brought back from a business trip to France as a kid.

From decades of eating blue cheese and much research on the topic of cheeses as a whole, here’s my take on the topic.

Is blue cheese safe to eat?

Blue cheese is an aged cheese cultured with the mold Penicillium, responsible for its distinct appearance, texture, flavor, and aroma. The acidity, salinity, and moisture of the cheese prevent the mold from producing mycotoxins and aflatoxins, two toxins harmful to humans, making blue cheese safe to eat.

Most of us consciously stay away from moldy foods because mold is typically a sign of food spoilage. But, when it comes to food safety, not all molds are created equal.

Some molds are dangerous for you because they produce two toxins called mycotoxins and aflatoxins. A 2014 study of mycotoxins, commonly found in nuts, corn, rice, and dried fruits, found that they “represent a considerable health risk to human health.”

Mycotoxins can affect your respiratory system, suppress your immune system, and even act as carcinogens. Aflatoxins, on the other hand, are poisonous, carcinogenic (known to cause cancer), and mutagenic (known to cause mutation of your cell’s genetic material) toxins.

Other molds, like Penicillium roqueforti used for the production of French Roquefort, Danish Blue, and English Stilton cheese, Penicillium glaucum used for making French Bleu d’Auvergne, Italian Gorgonzola, and Penicillium camemberti which produces German Cambonzola, are harmless since they don’t produce mycotoxins or aflatoxins when they’ve cultured cheese.

Penicillium roquefortiRoquefort cheese, Danish blue cheese (Danablu), English Stilton cheese, and some varieties of Gorgonzola
Penicillium glaucumBleu de Gex, Rochebaron, and some varieties of Bleu d’Auvergne and Gorgonzola
Penicillium camembertiCamembert, Brie, Langres, Coulommiers, and Cambozola
What mold is in your cheese?

“The combination of acidity, salinity, moisture, density, temperature, and oxygen flow creates an environment that is far outside the envelope of toxin production range for these molds,” artisan cheesemaker Yoav Perry writes in a Quora thread.

“In fact, this is true for almost all molds in cheese, which is the reason that cheese has been considered a safe moldy food to eat for the past 9,000 years.”

There you have it, folks. Penicillium mold grows and spreads inside blue cheese. Thanks to the special conditions for producing and storing the cheese, the mold can’t produce mycotoxins and aflatoxins, the two toxins known to cause harm to humans. 

As a matter of fact, blue can be good for you. Keep on reading to find out how.

Is Blue Cheese Good for You?

Blue cheese is a nutrient-rich cheese variety that’s high in calcium and a good source of many vitamins and minerals (like Cobalamin, Vitamin A, and Vitamin B-6). Consume blue cheese in moderation. Like many other dairy products, it’s also high in fat, salty, and cholesterol.

According to the USDA’s FoodData Central database, a 100 g serving of blue cheese has the following nutritional value:

  • Calories—353 kcal
  • Total fat—29 g
    • Of which Saturated fat—19 g
    • Of which Polyunsaturated fat—0.8 g
    • Of which Monounsaturated fat—8 g
  • Cholesterol—75 mg
  • Sodium—1,395 mg
  • Potassium—256 mg
  • Total carbs—2.3 g
    • Of which sugar—0.5 g
  • Protein—21 g
  • Vitamins and minerals (% Daily Value)
    • Vitamin A—15%
    • Calcium—52%
    • Vitamin D—5%
    • Cobalamin—20%
    • Iron—1%
    • Vitamin B-6—10%
    • Magnesium—5%

Blue cheese is one of the cheeses with the highest calcium content. A 100 g serving of blue cheese contains 528 mg of calcium, or 52% of the USDA’s Recommended Dietary Allowance (RDA) for calcium.

The calcium in blue cheese contributes to healthy bone structure and may help to fight obesity, WebMD reports. Studies have found that blue cheese consumption helps with managing levels of visceral fat around the abdominal area and maintaining gut health.

Penicillium roqueforti and Penicillium glaucum, the two molds used for making Roquefort, Stilton, Gorgonzola, and other blue cheese, have anti-bacterial properties. These molds produce antibacterial metabolites—bioactive compounds known to fight Gram-positive and Gram-negative bacteria.

How Blue Cheese Is Made

Before electricity and refrigeration, food was stored in cellars and caves. Their cold, dark, and humid environment allows for long-term storage of foods and beverages. But it also promotes the growth of mold.

Blue cheese is thought to have been discovered by accident in the 7th century, when a local shepherd from the French village of Roquefort-sur-Soulzon forgot his lunch of bread and cheese in a cave.

When he came across his lunch several months after, he allegedly found that it was cultured with mold. Obviously, the local shepherd must have been very hungry or really curious since he ate the cheese, found out about its goodness, and spread the word around town.

For centuries across Europe, blue cheese was ripened in caves and cellars using natural processes and traditional techniques. Today, blue cheese is carried by most grocery stores and commercially-produced using modern methods.

Blue cheese is made by adding Penicillium culture (along with the starter culture) to the milk. Harder cheeses are pierced and exposed to air when still young, which allows the mold to develop its distinct green or blue color. Softer cheeses, which are too creamy to allow this to happen naturally, are injected with mold.

The cheese is aged, typically for 1-6 months, graded, and sold. Since the best blue cheeses carry a Protected Designation of Origin (P.D.O.) from the European Union (EU), which means they’re made only in particular regions following strict recipes, they’re also pretty expensive.


Yes, blue cheese is safe to eat. Though it’s cultured by mold that can otherwise produce toxins, the acidity, salinity, and moisture of the cheese keep the mold from producing them.

Blue cheese is highly nutritious. At the same time, it’s a source of fat, salt, and cholesterol. As with any other dairy product, blue cheese is best enjoyed in moderation.

Add blue cheese to salads, burgers, pizzas, and pasta. It pairs exceptionally well with sweeter ingredients (since it balances the sweetness out with its saltiness and tanginess).

What’s your favorite blue cheese variety? Let me—and the rest of this post’s readers—know by leaving a comment below.

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Written by

Jim is the former editor of Home Cook World. He is a career food writer who's been cooking and baking at home ever since he could see over the counter and put a chair by the stove.