How to Tell If Cheese Is Bad (2024)

You bought a beautiful hunk of cheese from the farmers' market after the cheesemaker showed you an adorable photo of the cow whose milk went into it, or maybe the cute hipster at the cheesemonger convinced you take home something with a "bloomy rind" to add to your charcuterie board.

You store it in the deli drawer of your fridge until the perfect moment arrives, but when you retrieve your little piece of creaminess, you realize that there's something about it that doesn't feel quite right. Has it gone bad? Is it supposed to smell like that? Are those little splotches supposed to be there?

The answer really depends on the type of cheese, how it was stored, and what you're seeing or smelling, exactly. It's best to think of cheese as a living thing, much like fresh produce. The cultures or molds that give cheeses their distinctive flavor are living organisms that can die and start rotting. But whereas it's easy to tell that a weird smell or a fuzzy patch on a fruit means it's no longer safe to eat, it can be tricky to determine if a food has gone bad when it's already kind of stinky and moldy. Below, we break down how to tell if cheese is bad.

How Long Does Cheese Last in the Fridge Unopened?

An unopened package of cheese can last in the refrigerator for quite some time, especially if it's vacuum sealed. Vacuum-sealed cheeses also come with best-by dates on the packaging, which is the date through which the cheesemaker has determined the cheese will remain good to eat.

Don't get this confused with an expiration date, though. Best-by dates are simply the dates by which a producer can guarantee the flavor and texture of their product. Many aged cheeses, in particular, may still be good to eat after the best-by date. As for exactly how long an unopened package of cheese will last in the refrigerator, there is no single answer, as every type of cheese has its own shelf life. In general, though, you can expect hard cheeses to last the longest—up to six months. Fresher, soft cheeses, like cottage cheese and queso blanco, go bad much more quickly—think just a few weeks.

How Long Does Cheese Last in the Fridge Once Opened?

Once it's opened, there are several factors that affect how long cheese can last in the refrigerator. You may have heard terms like hard, soft and semi-soft used to describe cheeses. These terms refer mainly to the moisture content of each cheese. Soft cheeses, like Brie and chèvre, are very moist. This moisture is a perfect breeding ground for the good cultures and molds that make these cheeses flavorful and healthy, but it's also an ideal environment for harmful bacteria to take hold. Fresh soft cheeses, like cottage cheese, tend to go bad more rapidly because they are basically blank canvases for any kind of bacteria, both good and bad. Since we can't count on our refrigerators having the same climate and humidity as caves in France, there's little chance that your forgotten tub of cottage cheese will turn into the next Humboldt Fog instead of a serious health hazard. In general, most soft cheeses will last in the fridge for about a week once opened. Hard cheeses can last up to a month in the fridge after opening.

Signs Your Cheese Is Bad

The best tools to help you determine whether or not your cheese has gone bad are your senses, especially sight, smell and taste. Below, we spell out what you should look out for.

Smell

How a cheese smells is not only the best indicator of its quality before you put it into your mouth but also one of the best ways to determine whether your cheese is still safe to eat. If a mild cheese, like Monterey Jack or American, smells strong, like blue cheese or Limburger, then it's time to throw it away. Cheeses that are naturally pungent, like a blue cheese or Camembert, will have a strong ammonia smell to them once they go bad, similar to cat urine. If you are familiar with the smell of a favorite cheese, and the cheese you have smells like a much more concentrated version of what you're used to, it's probably a safe bet that it's no longer safe to eat.

Appearance

It's always good to check the appearance of cheese before purchasing it and shortly after you purchase it, too. Not only will you be able to see whether the cheese already has any signs of spoilage, but you will also familiarize yourself with how the cheese is supposed to look. It can also help to do a bit of research on a particular aged cheese you've just obtained. This can include asking your cheesemonger or researching photos and videos online. Once the cheese starts changing too much from its original appearance, it might be time to discard it. For example, many French soft cheeses have a white, fuzzy exterior that can look like bad mold but is completely safe to eat. If you start noticing patches of different types of fuzz in different colors or textures, that's a sign that the cheese has gone bad.

Taste

Many cheeses have very strong flavors, and the more you explore the world of cheeses, the more you'll find that some even tread the thin line between tasting delicious and tasting off. However, you should always keep in mind that even the stinkiest cheese has been cultured and aged in very controlled conditions. Your home refrigerator, on the other hand, does not offer the same conditions as a cheesemaker's aging room. A pungent cheese will still taste pleasant to a connoisseur. When it has gone bad, it will taste overly bitter or sour, or have a musty quality to it, like drinking water from a moldy pipe. And if a mild cheese all of a sudden has some character to it, don't assume you just aged your own cheese. Just throw it away.

What Happens If You Eat Spoiled Cheese?

If you have a healthy immune system, you may just experience a bit of indigestion if you accidentally eat a small amount of cheese that has spoiled. Many times, spoiled cheeses are affected by harmful mold, like black mold, and this may cause an allergic reaction in some individuals. In the worst instances, spoiled cheese can cause severe food poisoning. Consuming spoiled cheese will mostly affect your digestive system, causing you to experience gastrointestinal discomfort and loose stools. In severe cases, these symptoms may be accompanied by fever and chills. If you do feel ill after consuming cheese that you suspect was spoiled, please seek medical attention immediately. When in doubt, throw it out. No cheese is worth jeopardizing your health.

Tips for Storing Cheese in the Fridge

Cheeses require specific conditions to keep them fresh and tasting great, and the deli drawer in your refrigerator does a good job at providing your cheeses with the right temperature and humidity. These are two factors you should always pay attention to when storing cheese. An environment that is too humid and hotter than 45 degrees Fahrenheit is like an open invitation for bad bacteria and mold to make themselves at home on your cheese. While you don't need to worry so much about the humidity as long as you don't store your cheese with moist foods, like produce, it is important to check on your refrigerator's temperature. Unopened cheeses can be kept almost anywhere in the refrigerator as long as they are in a sealed container. Once you open a cheese, however, it's important to store it in a dedicated drawer, such as your fridge's deli drawer. For expensive aged cheeses, it's advised that you wrap your cheese in cheese paper or wax paper and not plastic wrap. The paper will allow the healthy cultures in your cheese to breathe, thus enhancing its flavor, and will also prevent it from getting too moist. Plastic wrap, on the other hand, can trap moisture and cause your cheese to go bad quickly.

Tips for Storing Cheese in the Freezer

Freezing changes the composition of foods. That's why frozen berries lose their firmness and octopus becomes oh-so-tender once it's been frozen. Similarly, freezing will change the composition of many, if not most, cheeses. One of the main things that freezing does to cheese is change its texture, especially if it's a smooth, creamy cheese. Young, semi-soft cheeses, like mozzarella and mild Cheddar, can become grainy and crumbly when frozen. However, they will still melt beautifully in dishes. On the other hand, hard cheeses, like Parmesan and pecorino, freeze and thaw quite well. Unopened, vacuum-sealed cheese can be stored as-is in the freezer. Opened cheeses should be wrapped tightly in plastic wrap and again in foil before freezing to prevent freezer burn. Because you are freezing the cheese, you don't have to take the same precautions you do with avoiding plastic wrap for refrigerated cheeses. You can also add smaller pieces of wrapped cheese to a freezer bag for extra protection.

How to Use Up Cheese Before It Goes Bad

If you're a cheese fanatic, using up cheese before it goes bad is just a matter of grabbing some crackers and maybe a glass of wine. However, we're sometimes left with a lot of cheese that no amount of water crackers and cabernet sauvignon can help us finish. It's in these instances that we need some go-to cheesy recipes where the cheeses are interchangeable, so no matter what you're trying to use up it always works to make a great meal or snack. These cheesy potato packets, for instance, call for Gruyère but can use any type of cheese or even a combination of cheeses. You can also make a decadent snack you may not want to share, like this Hasselback Cheesy Garlic Bread. Macaroni and cheese recipes are also a great way to use up a bunch of different bits of cheese you may have left over. And if you're a fan of kitchen experiments, you may try your hand at making homemade cheese dip by melting all of your bits of cheese. For inspiration, you can also take a look at our selection of cheesy hot dips to enjoy whenever you want.

Bottom Line

While cheeses can be aged for over a decade, remember that cheesemakers are highly trained professionals working in very controlled environments where they can ensure the quality and safety of their cheeses. Your refrigerator, on the other hand, is nothing like a cheese cave. Nevertheless, with some proper storage and knowledge on how to tell if a cheese has gone bad, you can safely store your cheeses in your home and enjoy them without worrying about falling ill. Remember to use your sense of smell and check a cheese's appearance before putting it in your mouth. If you do feel ill after eating a piece of cheese that might be spoiled, it's best to give your health care provider a call.