Parmesan Cheese: Can It Go Bad? How to Tell?

Last Updated on January 17, 2024 by Aaron

Parmesan cheese is a type of hard Italian cheese that is made from cow’s milk. It has a nutty, salty flavor and is often used in pasta dishes, salads, and soups.

Parmesan cheese is a popular kitchen condiment, but did you know it can go bad?

In this blog post, we will discuss the signs of spoilage and how to tell if parmesan cheese has gone bad. We will also explore why parmesan cheese sometimes makes people sick and how long it will last after opening.

Stay safe and enjoy your next bowl of spaghetti with extra parmesan!

Can Parmesan Cheese Go Bad?

Parmesan cheese is a hard cheese that typically has a good shelf life — thanks to its long curing period of 10-12 months minimum. However, like all cheeses, it can go bad quickly if not stored properly.

The signs of spoilage in parmesan cheese are similar to other cheeses, such as off odor, mold, and a slimy texture.

If you are not sure whether the cheese has gone bad, you can simply take a good sniff of it. If the cheese smells sour or ammonia-like, it is best to discard it.

One of the main signs of spoilage in parmesan cheese is an off odor. It is worth noting that a little bit of a sour smell is fairly normal. However, if the smell is overwhelming, it is a clear sign that the cheese has gone bad. We have further discussed why parmesan smells like vomit, fruity, or plastic previously.

If you see mold on parmesan cheese, you can cut away 1 inch around the moldy area and check if the rest of the cheese is safe to eat. Mold can’t penetrate far in hard-aged cheeses like parmesan, therefore it is generally safe to eat the cheese if there is only a small area of mold present.

However, it is always best to use your own judgement and if the mold has spread too much, it is best to discard the cheese. It’s also important to remember that mold can have different colors and may be visible or invisible to the eye, so always be careful when consuming any cheese that has mold. See the image below:

Mold on parmesan may look like this:

If the parmesan cheese has a slimy texture, it is most likely already long past its prime and not nice to eat. The parmesan may also appear dry and oily when the cheese dried out.

When inspecting parmesan cheese, it is important to look for a consistent color throughout the cheese. The presence of brown or green spots may indicate spoilage, and the cheese should be discarded in that case.

Can you get sick from expired parmesan cheese?

Yes, you can get sick from eating expired parmesan cheese. The cheese might have gone bad and contains harmful bacteria, such as listeria or E. coli. It’s possible that you may have food poisoning or stomach upset caused by consuming expired or contaminated parmesan. The symptoms of food poisoning include nausea, vomiting, and diarrhea. If you are experiencing any symptoms after eating parmesan cheese, it is best to speak with your doctor.

Why does parmesan cheese make me sick?

There can be various reasons why parmesan cheese can make a person feel sick. One possibility is an allergy or intolerance to one of the ingredients in the cheese, such as lactose or casein.

Parmesan cheese contains a low amount of lactose — typically about 0 to 5 grams per 100g serving of parmesan. Certain brands may have lactose (as in carbohydrate) too low to be detectable, for example, the Reggano Grated Parmesan by Aldi nutrition contains 0 lactose, while Schnucks Parmesan nutrition contains about 7 grams of lactose in the same serving. Read more about lactose and parmesan here.

Another possibility is the high sodium content in parmesan cheese. A one-ounce serving of Kraft parmesan contains about 450 mg of sodium, that’s over 20% of the daily intake limit! Overconsuming can cause dizziness, stomach cramp, and nausea.

So, how long does parmesan cheese last?

Parmesan cheese is a hard, aged cheese, which means it can last longer than most other types of cheese. When stored properly in the refrigerator, a block of unopened parmesan cheese can last up to 6 months. Reduced to 1-2 months if opened. However, pre-grated or shredded parmesan cheese has a shorter shelf life and should be used within 1-2 weeks after opening the package.

It’s important to note that even if stored properly, the quality of the cheese may deteriorate over time, and it may develop an off-flavor or texture. Always check for signs of spoilage, such as mold, off-odor, or an unusual texture before consuming any cheese.

It’s also worth noting that parmesan cheese can be frozen for up to 8 months without affecting the flavor and texture of the cheese. Read more about freezing parmesan in my other post.

When stored properly in a cool and dry area, a parmesan wheel can last for up to 12 months or more. However, the exact shelf life of a parmesan wheel can vary depending on the specific brand and how it was produced. It is also recommended to store the cheese in a wine or cheese cellar, where the temperature and humidity can be controlled.

Can parmesan be left out or stored at room temperature?

Without refrigeration, parmesan cheese can last for 8 to 12 hours. However, it is not recommended to leave parmesan cheese out at room temperature for an extended period of time. Parmesan cheese, like most other types of cheese, is perishable and should be stored in the refrigerator to slow down the growth of bacteria.

When stored at room temperature, parmesan cheese can spoil quickly due to the warm temperatures and humidity. The cheese can develop mold much more quickly. Even if the cheese appears to be fine, it may contain harmful bacteria that can cause food poisoning.

If you plan to serve parmesan cheese at room temperature, it’s best to take it out of the refrigerator 30 minutes to 1 hour before serving to allow it to come to room temperature. Once the cheese is served, any remaining should be placed back in the refrigerator as soon as possible.

It’s always best to store cheese in the refrigerator, wrapped in a cheese paper or plastic wrap, to maintain its quality and prevent spoilage.

How to store parmesan cheese?

It’s fine to store parmesan cheese in its original package. Also, you can simply wrap it in a plastic bag and place it in an airtight container. And It is best to consume it within two weeks after opening.

Storing parmesan cheese properly can help to extend its shelf life and maintain its quality. Here are some tips for storing parmesan cheese:

  1. Wrap the cheese: Wrap the cheese in a cheese paper or plastic wrap to protect it from air and moisture. This will help to slow down the growth of bacteria and prevent the cheese from drying out.
  2. Store in the refrigerator: Parmesan cheese should be stored in the refrigerator, ideally in the cheese drawer or on a low shelf where the temperature is between 33 to 40°F (0.5 to 4.4°C). Avoid storing the cheese near the freezer or in the door where the temperature can fluctuate.
  3. Avoid cross-contamination: Keep parmesan cheese away from other foods that have strong odors, such as onions or garlic, to prevent cross-contamination.
  4. Consume within the expiration date: Always check the expiration date on the cheese and consume it before that date.
  5. Use a cheese grater or plane: When you’re ready to use the cheese, use a cheese grater or plane to shave off only what you need, rather than cutting it with a knife. This will help to reduce the amount of surface exposed to the air and prolong the shelf life of the cheese.
  6. Keep the rind: Parmesan cheese comes with a rind, do not cut it off. The rind is edible and it helps preserve the cheese, keeping it from drying out.

By following these tips, you can help to ensure that your parmesan cheese stays fresh and delicious for as long as possible.


  1. Mayo Clinic – Moldy Cheese
  2. IIBFY – Parmesan
  3. Italia Regina – Store Parmesan
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