What Happens If You Eat Bad Parmesan Cheese?

Cheese lovers know that Parmesan is more than just a topping for pasta or pizza. This hard Italian cheese can be enjoyed on its own or grated to enhance various dishes. Parmesan cheese actually refers to two separate cheeses that people use interchangeably – Parmigiano-Reggiano and Grana Padano. Both are protected designations of origin by the European Union. Authentic Parmesan has a delicious nutty and savory flavor and granular texture that adds a punch of umami to recipes.

With its ubiquity in the kitchen, Parmesan is often purchased in large wedges or quantities and stored for later use. But what happens if this cheese goes bad before you get to all of it? Can eating spoiled Parmesan make you sick? In this article, I’ll walk through how to tell if your Parmesan cheese is still good, signs that it has gone bad, and what to do if you accidentally eat rancid Parmesan.

Does Parmesan Cheese Go Bad?

First, let’s clear up whether Parmesan cheese actually expires and goes bad. With its hard texture and low moisture content, Parmesan is what is known as a “hard cheese.” This class of cheese generally has a longer shelf life than soft cheeses like mozzarella or brie. An unopened wedge of good quality Parmesan can last in the refrigerator for up to a year past its printed expiration date. Of course, the cheese may become more pungent, dry, and crumbly the longer you store it.

Once you cut into the cheese or buy pre-grated Parmesan, it will spoil faster. Yet it still keeps longer than other dairy products. Tightly sealed grated Parmesan will last up to 4 to 6 months refrigerated and unopened shredded Parmesan is good for 2 to 3 months. If you freeze grated Parmesan, you can extend its shelf life to 6 months or longer.

So generally, Parmesan cheese does not expire quickly. With proper storage like sealing airtight and refrigerating, even opened Parmesan wedges and grated cheese can last for many months past the sell-by or use-by date printed on the packaging. But there will come a time when your Parmesan wedge has dried up or when your grated Parmesan takes on an unpleasant odor indicating it has spoiled.

What Happens If You Eat Expired Parmesan Cheese?

Now we get to the crux of the matter – is it bad to eat Parmesan cheese past its expiration date or showing signs of age?

The key thing to understand is that the date stamped on Parmesan’s packaging is actually just a “best by” or “use by” date, not an expiration date indicating when the product becomes unsafe. Because of its long shelf life, Parmesan cheese is typically still good for weeks or months past this printed date.

As the cheese ages and oils slowly oxidize, the flavor and texture degrade which is why the manufacturer recommends using it by a certain date. But expired Parmesan won’t necessarily make you sick. As long as the cheese hasn’t become obviously moldy or smelly, eating it should not have negative effects.

Some signs of Parmesan going bad include:

– Mold growth – White mold on hard cheeses like Parmesan is generally safe to cut off. But if mold spreads through most of the wedge, discard it.

– Sour or “off” smell – Rancid Parmesan gives off a pungent aroma. If it smells unpleasant, it should not be eaten.

– Odd colors – Gray, green, or blue discoloration indicates spoilage. The natural outer rind may darken as it ages but the interior should remain light-colored.

– Crumbly texture – Parmesan will become more brittle as it dries out but crumbling into powdery bits when you grate it means it’s too old.

Your nose and common sense are the best tools for determining if aged Parmesan cheese has gone bad or not. The old adage applies – when in doubt, throw it out.

What To Do If You Eat Bad Parmesan Cheese

We’ve determined that Parmesan lasts a long time and eating it past its prime won’t make you deathly ill. But what if you accidentally eat Parmesan that’s clearly gone bad?

First, don’t panic. The preservatives and aging of hard cheeses like Parmesan make it unlikely to cause severe food poisoning. But some key steps include:

– Stop eating the rancid cheese to limit exposure.

– If you feel nauseous or ill, drink fluids and call your doctor.

– Monitor yourself for symptoms like vomiting, diarrhea, dizziness, etc. for the next 48 hours.

– Discard the spoiled Parmesan so others don’t accidentally eat it.

– Call the manufacturer if you believe the product was mislabeled.

With its extensive shelf life, eating expired or bad Parmesan cheese rarely leads to serious sickness in healthy adults. But moldy, smelly, or rancid Parmesan can make you quite uncomfortable for a day or two. So take care to store your Parmesan properly. Follow your senses, and toss aging cheese out when it’s clearly past its prime. Then you can safely enjoy tasty Parmesan for many months without worry.

How Long Does Fresh Parmesan Cheese Last?

Parmesan’s shelf life depends on a few factors:

– Storage method – Proper refrigeration and sealing in airtight bags or containers extends shelf life.

– State of cheese – Unopened blocks last much longer than opened or grated Parmesan.

– Age and quality – Fresher and higher quality Parmesan lasts longer. Pre-grated cheese with additives spoils faster.

Here are some general guidelines for how long Parmesan cheese lasts:

– Unopened Parmesan wedge – About 1 year refrigerated; 6+ months in freezer.

– Opened Parmesan block – 3 to 6 months tightly wrapped in fridge.

– Pre-grated Parmesan – 3 to 5 months sealed in fridge; 6+ months in freezer.

– Homemade grated Parmesan – 1 to 4 weeks airtight in fridge; 2 to 6 months frozen.

– Parmesan cheese rind – 2 to 3 months wrapped, refrigerated.

Though Parmesan keeps for a relatively long time, it’s always important to watch for signs that your cheese is aging and use your senses to check if it has gone bad.

How Long Does Sprinkle Parmesan Cheese Last?

The shelf stable Parmesan cheese sold in a can or shaker with anti-caking agents is convenience packaging that allows the Parmesan to avoid refrigeration. Unopened, this style of Parmesan will last about 1 year in your pantry. Once exposed to air, it’s best to refrigerate sprinkle Parmesan. Then it will keep for 6 to 8 months.

You can also freeze sprinkle Parmesan to prolong its shelf life to around 1 year. Just keep it in an airtight container or bag. This powdered aged cheese lasts remarkably long thanks to its low moisture and high acidity. A “best by” date is printed on the packaging, but the cheese is still safe indefinitely as long as it hasn’t gotten noticeably stale or smelly.

How Long Does Grated Parmesan Last After Opening?

Grated Parmesan cheese that you buy pre-shredded or grate at home has a shorter shelf life than Parmesan wedges. But it still lasts surprisingly long.

Tightly sealed, grated Parmesan keeps in the fridge for:

– 3 to 5 months past its “best by” date.

– 4 to 6 weeks after opening for homemade grated.

– 2 to 3 months after opening for pre-packaged grated.

Freezing grated Parmesan for storage can extend its shelf life for an additional 2 to 6 months. Properly stored, shredded or grated Parmesan lasts for many weeks or months after its use-by date. Always do a smell and texture check before using aged grated Parmesan in your cooking.

Will Parmesan Go Bad if Not Refrigerated?

Ideally, all Parmesan cheese should be refrigerated, whether freshly cut from a block or pre-grated. Refrigeration at 40°F or below preserves Parmesan’s quality and prevents it from drying out or becoming moldy. However, you may be wondering:

– Can you store Parmesan at room temperature?
– Is Parmesan safe unrefrigerated?

If it’s for a short time, such as a couple hours out on the counter, Parmesan will be just fine. Hard cheeses like Parmesan fair better than other cheeses when left unrefrigerated. Given its low moisture and aging process, properly stored Parmesan can even keep for up to 2 weeks out of the fridge before quality start to decline.

Of course, it’s not recommended to keep Parmesan out at room temperature for extended periods. Warmer conditions cause Parmesan to sweat, dry out faster, and grow mold more quickly. For food safety and the best taste, you should refrigerate opened or grated Parmesan within 1 to 2 hours after opening. An unopened Parmesan wedge can be left out at room temperature for up to 1 week before refrigerating.

In Conclusion

Parmesan cheese has an exceptionally long shelf life compared to other cheeses. Thanks to its aging process, hardness and low moisture, both wedge and grated Parmesan stay fresh for many weeks or months when properly stored in the refrigerator.

While Parmesan can last for over a year refrigerated, its flavor and texture will degrade over time. Expired Parmesan may become more pungent or develop white mold but is generally still safe to eat. Signs that Parmesan has truly spoiled and should be discarded include black/green mold, orange rind, foul smell, sliminess, or bitter taste.

With its high acidity and preservatives, eating rancid Parmesan is unlikely to cause serious illness in healthy adults but can lead to stomach upset. So use your senses, refrigerate your Parmesan, and enjoy it for as long as possible within its extensive shelf life.