People used to say that eating the mold on cheese was basically like taking penicillin; something “good for you” and even medicinal. That idea isn’t entirely accurate. 

While it’s true that some cheeses are made using carefully controlled strains of mold, such as those related to Penicillium, the molds found in cheese are not the same as the antibiotic penicillin used to treat infections. In fact, only specific molds grown under precise conditions are safe to eat, and many wild molds that appear on spoiled food can be harmful. 

Cheese is one of the oldest and most diverse foods in human history, prized for its rich flavors, textures and aromas. Mold-ripened cheeses often spark curiosity and sometimes concern. Can cheeses that develop molds actually be eaten safely? The answer is yes, but with important distinctions.

Certain cheeses are intentionally made with mold as part of their production process. These include well-known varieties like blue cheeses, Brie and Camembert. In these cases, specific strains of mold are carefully introduced under controlled conditions. For example, blue cheeses develop their characteristic veins from Penicillium roqueforti, while soft-ripened cheeses like Brie rely on Penicillium camemberti to form their white, bloomy rind. These molds are not only safe to eat but are essential to the cheese’s flavor and texture, contributing to earthy, tangy and sometimes mushroom-like notes.

However, not all mold on cheese is desirable. When cheese is stored improperly or kept for too long, unwanted molds can grow on its surface. Whether the cheese is still safe to eat depends largely on the type of cheese. Hard and semi-hard cheeses, such as cheddar or Parmesan, are more resilient. If mold appears on these cheeses, it is often safe to cut away the affected area, typically at least one inch (about 2.5 centimeters) around and below the visible mold, because the dense structure of the cheese prevents the mold from penetrating deeply.

In contrast, soft cheeses like ricotta, cream cheese or fresh mozzarella are more vulnerable. Their high moisture content allows mold to spread more easily beneath the surface, even if it is not visible. In these cases, the safest approach is to discard the entire product. The same caution applies to shredded or sliced cheeses, where mold can quickly contaminate multiple pieces.

Another important consideration is food safety. Some molds can produce mycotoxins, harmful substances that may pose health risks if consumed in significant amounts. While the molds used in cheesemaking are carefully selected and monitored, wild molds that develop unintentionally are unpredictable. For individuals with compromised immune systems, allergies or sensitivities, even small exposures to mold may cause adverse reactions.

Proper storage plays a key role in preventing unwanted mold growth. Cheese should be kept in the refrigerator, ideally wrapped in breathable material such as wax paper or cheese paper, which allows it to maintain the right humidity without trapping excess moisture. Regularly checking stored cheese for changes in smell, texture or appearance can also help ensure it remains safe to eat.

In conclusion, mold in cheese is not inherently a sign of spoilage; in fact, it can be a hallmark of some of the world’s most beloved varieties. The key lies in understanding the difference between intentional, beneficial molds and those that indicate spoilage. By recognizing these distinctions and practicing proper storage and handling, cheese lovers can enjoy a wide range of flavors safely and confidently.

Here are well known cheeses where mold is intentional, safe and essential to their flavor and texture:

Blue-veined cheeses (internal mold)

These cheeses have mold cultures added that grow inside, creating veins:

Roquefort—A classic French sheep’s milk cheese with strong, tangy flavor 

Stilton—Rich and crumbly, often slightly sweet and nutty 

Gorgonzola—Comes in creamy (Dolce) and firmer (Piccante) varieties 

Danish Blue—Sharper and saltier than many others 

Cabrales—Very bold, often aged in caves 

Bloomy-rind cheeses (white surface mold)

These have a soft white rind formed by beneficial mold:

Brie—Creamy interior with a mild, buttery flavor 

Camembert—Earthier and more intense than Brie 

Coulommiers—Similar to Brie but smaller and often richer 

Washed-rind cheeses (bacteria plus occasional mold)

These develop strong aromas through washing, sometimes with surface mold as part of aging:

Taleggio—Funky smell but surprisingly mild taste 

Époisses—Very pungent, creamy, and complex 

Munster—Strong aroma with a smooth texture 

Natural-rind aged cheeses

Some cheeses develop harmless molds on their rind during aging:

Tomme de Savoie—Rustic rind with mild, nutty interior 

Gruyère—Occasionally has natural rind mold, typically trimmed off.

Bottom line:

If in doubt, throw it out.

Michael Kossove is professor emeritus and an adjunct professor of microbiology at Touro University’s School of Health Sciences. He is a polio researcher, international polio lecturer and polio survivor. He can be reached at Professormike2@aol.com.