Is It Safe to Eat Moldy Cheese? It Depends on the Cheese
Many people have found a forgotten block of cheddar with a fuzzy patch of blue or white and wondered if it's still salvageable. The answer, which may surprise you, is that it depends almost entirely on the type of cheese. A key distinction must be made between harmless, intentional mold used in cheesemaking, such as the veins in blue cheese or the rind on Brie, and unintentional mold that signals spoilage. The rule of thumb comes down to the cheese's moisture content, which dictates how deeply mold can penetrate and whether dangerous bacteria might be co-existing.
The Science of Mold on Cheese
Mold is a type of microscopic fungus that produces spores and has root-like threads, or mycelium, that invade the food it colonizes. The fuzzy growth you see on the surface is only part of the organism. In soft cheeses, with their high moisture content, these mycelium threads can quickly spread far below the visible surface, contaminating the entire block. In addition, moisture-rich environments are a breeding ground for other harmful bacteria like Listeria, Salmonella, and E. coli which may be present alongside the mold. For this reason, soft cheeses should be immediately discarded upon discovering unwanted mold.
Hard and semi-hard cheeses, with their dense structure and low moisture, are a different story. The mold and its roots have a much harder time penetrating deep into the cheese. This is why for cheeses like cheddar or parmesan, it is often safe to salvage the rest of the block by cutting away the contaminated portion.
Potential Health Risks of Eating Moldy Cheese
For healthy individuals, accidentally consuming a small amount of mold from spoiled cheese will likely result in no ill effects beyond an unpleasant taste. The digestive acids in the stomach are usually strong enough to neutralize the mold spores. However, there are still risks to consider:
- Digestive Upset: Larger amounts of mold can cause mild digestive issues such as nausea or stomach pain.
- Allergic Reactions: Some people are allergic to specific types of mold. Eating moldy food could trigger an allergic reaction with symptoms like sneezing, a runny nose, or an itchy throat.
- Mycotoxins: Certain molds can produce toxic substances called mycotoxins. While mycotoxins are more common in grains and nuts, and extremely rare in dairy, ingesting large doses is very dangerous. It's impossible to know just by looking if a mold is toxic.
- Vulnerable Populations: People with compromised immune systems, older adults, pregnant women, and young children are more susceptible to illness from mold and should avoid any potentially contaminated cheese.
A Practical Comparison of Cheese Types
To make an informed decision, here's a quick guide based on cheese type:
| Cheese Type | Example | Can You Salvage? | Why? |
|---|---|---|---|
| Hard & Semi-Hard | Cheddar, Parmesan, Swiss | Yes, with careful trimming. | The dense texture prevents mold roots from penetrating far below the surface. |
| Soft & Crumbled | Cottage cheese, Ricotta, Shredded cheese, Cream cheese | No, discard completely. | High moisture content allows mold and bacteria to spread throughout the product invisibly. |
| Mold-Ripened | Brie, Camembert, Blue cheese | Depends. | Intentional mold is safe. Unwanted, fuzzy, or off-color mold should be cut away on the surface, but soft, mold-ripened cheeses should be discarded if mold looks suspicious. |
How to Properly Handle Moldy Hard Cheese
If you have a hard cheese and decide to trim the mold, follow these steps carefully to ensure food safety:
- Cut Generously: The USDA recommends cutting away at least one inch around and below the moldy spot.
- Prevent Cross-Contamination: Do not let your knife touch the moldy part as you cut. Immediately clean the knife and any surfaces the mold came into contact with.
- Re-wrap Properly: After trimming, rewrap the remaining cheese tightly in new, clean wax paper, parchment paper, or foil to protect it from further contamination. Avoid using the original wrapper.
- Discard Trimmings Safely: Wrap all moldy pieces in a sealed plastic bag and place them in a covered garbage can to avoid releasing spores into the air.
Preventing Mold Growth on Cheese
Proper storage is the best defense against mold. Following these practices can significantly extend the life of your cheese:
- Refrigerate Promptly: Store cheese in the refrigerator at temperatures between 34–38°F (1–3°C).
- Use the Right Wrap: After opening, rewrap cheese in cheese paper, parchment paper, or wax paper. This allows the cheese to breathe while preventing moisture buildup that fosters mold growth. For extra protection, place the wrapped cheese in a loosely sealed plastic bag or airtight container.
- Cleanliness is Key: Regularly clean your refrigerator, especially the cheese drawer or crisper. Mold spores can linger and contaminate other items.
- Mind the Neighbors: Store cheese away from strongly scented foods, as cheese can absorb odors.
Conclusion
In short, while eating a tiny, accidental nibble of moldy hard cheese won't likely harm a healthy adult, it's a food safety gamble that's often not worth the risk, especially with softer varieties. The key takeaway is to act decisively based on the cheese type: trim hard cheeses with a generous margin, but always toss any soft, crumbled, or shredded cheese showing signs of unwanted mold. By understanding the science and practicing proper handling and storage, you can keep your cheese fresh and your health safe.
