How long does block of Parmesan cheese last?

Parmesan cheese, known as the King of Cheeses, is a hard Italian cheese with a granular texture and intense, nutty flavor. Parmesan comes in wedge-shaped blocks or grated and can be used for grating, shredding, or crumbling over a variety of dishes. But how long does an unopened block of Parmesan cheese actually last? Here are some quick answers to common questions about Parmesan cheese shelf life.

Does Parmesan cheese expire?

Yes, Parmesan cheese does eventually expire and has a limited shelf life. However, unopened Parmesan can stay fresh in the refrigerator for a remarkably long time. An unopened wedge of Parmesan cheese will typically stay good for about:

  • 2 months past the “best by” date on the package
  • 6 months to 1 year past the purchase date (if no best by date)

How can you tell if Parmesan cheese has gone bad?

Here are some signs that your Parmesan wedge has spoiled and should be discarded:

  • Mold growth – any fuzzy white or blue mold
  • Dry, crumbly texture – aged Parmesan should still be granular and slightly hard
  • Ammonia smell – good Parmesan has a nutty, salty aroma
  • Off flavors – rancid, bitter, or sour taste

What happens if you eat expired Parmesan cheese?

Eating small amounts of expired Parmesan is generally safe, especially if there are no signs of spoilage. At worst, heavily expired Parmesan may cause temporary digestive upset like nausea, vomiting, or diarrhea if high levels of bacteria are present. Always inspect Parmesan and discard if you see any molds, foul odors, or sliminess.

How to store Parmesan cheese properly?

To maximize Parmesan’s shelf life, proper storage is key. Here are some tips for storing Parmesan cheese:

  • Keep Parmesan tightly wrapped in plastic wrap or parchment paper until ready to use.
  • Store in the refrigerator. The cold temperature (34°F to 38°F) slows mold growth.
  • Place Parmesan in a sealed container or bag if storing for longer than a month.
  • Keep away from moisture and condenstion that can breed mold.

Can you freeze Parmesan cheese?

Parmesan can be frozen to extend its shelf life significantly. To freeze Parmesan cheese blocks:

  • Double wrap in plastic wrap and aluminum foil.
  • Place in freezer bags or airtight containers, removing as much air as possible.
  • Freeze for up to 6 months.
  • Thaw in the refrigerator before using.

Note that freezing may accelerate moisture loss and texture changes. Grated Parmesan can also be frozen but may clump slightly upon thawing.

What are the best ways to use up Parmesan cheese?

If you have Parmesan cheese that’s nearing the end of its prime, here are some great ways to use it up:

  • Grate or crumble over pasta, salads, pizza, risottos
  • Add to seasoned breadcrumbs or panko for coating chicken, fish, etc.
  • Blend into dips, spreads, pestos
  • Top casseroles, gratins
  • Stir into soups, stews, risotto
  • Mix into meatballs, meatloaf

Using Parmesan in cooked dishes can minimize noticeable changes in texture from aging. Combine Parmesan with other ingredients to balance any harsh flavors.

How Long Does Grated Parmesan Cheese Last?

Grated Parmesan cheese is convenient for quickly sprinkling onto dishes but has a shorter shelf life than Parmesan wedges. Here is how long grated Parmesan cheese lasts:

Storage Method Fridge Shelf Life
Original packaging, unopened 3 to 4 months past the printed best by date
Original bag, opened 3 to 4 weeks
Resealed container 2 to 3 months
Freezer 6 months

As with wedges, keep refrigerated and check for mold, souring, or drying. Use frozen grated cheese within recommended time.

How can you tell if pre-grated Parmesan cheese is bad?

Signs that grated Parmesan has gone bad include:

  • Grayish or yellow discoloration
  • Hard, dry clumps
  • Mold development
  • Sour or rancid smell
  • Bitter taste

Discard grated Parmesan at the first signs of spoilage. When in doubt, throw it out.

Does grated Parmesan cheese mold?

Yes, grated Parmesan cheese can grow mold due to the increased surface area exposed to air. Mold can appear around 3-4 weeks after opening. Refrigeration and minimal moisture exposure help prevent molding. However, always inspect grated cheese carefully before use. Any mold at all is a sign to discard the product.

Can you freeze grated Parmesan?

Freezing extends the shelf life of grated Parmesan significantly. To freeze:

  • Portion grated cheese into airtight freezer bags or containers.
  • Remove as much air as possible.
  • Lay bags flat to freeze.
  • Freeze for up to 6 months.
  • Thaw in fridge before use.

Frozen grated cheese may become slightly damp upon thawing but can be blotted dry with a paper towel.

Does Parmesan Cheese Go Bad?

Yes, Parmesan cheese does eventually go bad once it surpasses its shelf life. As a hard Italian cheese made from cow’s milk, Parmesan contains bacteria that can lead to spoilage and compromise safety if left for too long.

However, Parmesan’s low moisture content and hard texture allow it to keep significantly longer than many other cheeses, especially when stored properly. Signs that Parmesan has spoiled include mold growth, changes in color or texture, and sour or “off” odors.

What causes Parmesan cheese to go bad?

There are a few main factors that can lead to Parmesan cheese going bad:

  • Moisture: Any moisture that gets introduced to Parmesan can allow mold growth. Keeping Parmesan well-wrapped until use helps prevent this.
  • Oxygen: Exposure to too much air causes Parmesan’s fats to oxidize and develop off-flavors.
  • Bacteria: Harmless lactic acid bacteria are used to make Parmesan. But other spoilage bacteria can develop over time, especially if contamination occurs.
  • Age: Even with proper storage, Parmesan’s flavor, texture, and quality deteriorate over months-long aging.

Following proper storage methods and discarding Parmesan at the first signs of spoilage can help prevent consumption of bad cheese.

How long can Parmesan cheese sit out?

Parmesan cheese is best kept refrigerated both before and after opening. At room temperature, Parmesan can start growing mold or bacteria within 1-2 hours if exposed to air or moisture:

  • Unopened Parmesan wedges – 1 hour
  • Opened Parmesan block – 30 minutes
  • Grated Parmesan – 1 hour

For optimal freshness and food safety, limit Parmesan’s time sitting out on the counter or table. After use, tightly rewrap or place Parmesan back into the refrigerator. Discard Parmesan left for longer than 2 hours at room temperature.

What happens if you eat moldy Parmesan cheese?

It’s best to avoid eating moldy Parmesan cheese. While Parmesan rinds can safely develop harmless white mold as they age, any blue, green, or black mold is unsafe. Consuming moldy cheese can cause food poisoning symptoms like:

  • Nausea, vomiting
  • Stomach cramps, diarrhea
  • Headache, fever
  • Cough, sore throat

In rare cases, moldy cheese can even cause severe allergic reactions or toxic mold infection. When in doubt, cut away and discard any moldy parts or toss the entire Parmesan block.

How To Store Parmesan Cheese

Proper storage is key for extending Parmesan cheese’s shelf life and preventing spoilage. Here are some tips for storing Parmesan wedges, grated cheese, and opened packages:

Storing Parmesan wedges:

  • Keep Parmesan wedges tightly wrapped in plastic wrap, parchment paper, or cheese paper.
  • Place inside a sealed container or bag if storing for over 1 month.
  • Always store Parmesan cheese in the refrigerator. Maintain a temperature between 34°F and 38°F.
  • Avoid freezing and thawing cycles. Allow Parmesan to come to room temperature before serving.
  • If mold develops on an Parmesan wedge, cut away mold at least 1 inch around the affected area.

Storing grated Parmesan:

  • Keep unused grated Parmesan cheese sealed in original bag.
  • Once opened, transfer to an airtight container and press out air.
  • Always store in the refrigerator.
  • To freeze, portion into airtight bags or containers leaving no headspace.

Storing opened Parmesan:

  • Tightly rewrap any leftover Parmesan pieces in plastic wrap or original packaging.
  • Use within 2 weeks for best quality.
  • Never return Parmesan to the original bag after opening.
  • Always return to refrigerator immediately after use.

Following proper storage methods can help maximize Parmesan’s shelf life and prevent premature spoilage. Discard Parmesan at the first signs of mold or off-smells.

Does Parmesan Cheese Need To Be Refrigerated?

Yes, Parmesan cheese always requires refrigeration to maintain quality and prevent spoilage. Unlike some hard cheeses, Parmesan should not be left at room temperature. Proper refrigerated storage helps prolong Parmesan’s shelf life.

Should unopened Parmesan be refrigerated?

Yes, Parmesan should be refrigerated in its original packaging until opened for the first time. Keeping unopened Parmesan cheese refrigerated helps:

  • Slow mold growth
  • Prevent bacteria from multiplying
  • Maintain fresher flavor
  • Avoid texture changes or drying out

Leaving factory-sealed Parmesan wedges or grated packages at room temperature can shorten the shelf life drastically. Refrigerate promptly after purchase.

Should opened Parmesan be refrigerated?

Absolutely. Once opened, Parmesan cheese must be tightly rewrapped and stored in the refrigerator. Exposing opened Parmesan to air and warmer temperatures increases the risk of fast mold growth and bacteria overgrowth.

Follow these steps to refrigerate opened Parmesan properly:

  • Rewrap tightly in plastic wrap or aluminum foil.
  • Place in an airtight container if storing for more than 1 week.
  • Return to the coldest area of the refrigerator.
  • Label with date opened.

Properly stored in the fridge, opened Parmesan wedge can last 2 months or longer past its printed date.

Can you store Parmesan cheese at room temperature?

It’s not recommended. Parmesan cheese should never be left out at room temperature for extended periods. Without refrigeration:

  • Unpacked wedges can mold within 1-2 days.
  • Off-flavors and dryness develop.
  • Bacteria multiply faster at warmer temperatures.

Briefly removing Parmesan to bring to room temperature before eating poses minimal risks. But always refrigerate Parmesan cheese right away after purchase and rewrap tightly after each use.

How Long Does Parmesan Cheese Last In The Fridge?

Properly stored in the refrigerator, Parmesan cheese can last between 6 months to 1 year past its purchase date if unopened. Here’s how long refrigerated Parmesan lasts:

  • Unopened Parmesan wedge: Up to 1 year past printed date
  • Sealed grated Parmesan: 3-4 months past printed date
  • Opened Parmesan wedge: 2-4 months
  • Opened grated Parmesan: 3-4 weeks

How long does Parmesan last after opening?

An opened block of Parmesan will stay fresh in the fridge for:

  • 2 weeks, kept tightly wrapped in original packaging
  • 1 month, wrapped in plastic wrap or foil
  • 2-4 months, stored in an airtight container

Properly rewrap Parmesan after each use and check frequently for mold once opened. Use within 2 weeks once texture or flavor decline.

How long does grated Parmesan cheese last in the fridge?

Tightly sealed, grated Parmesan lasts for 3-4 months past its printed expiration date when refrigerated. Once opened, it will stay good for:

  • 3-4 weeks in the original bag
  • 2-3 months transferred to an airtight container

Discard any grated Parmesan that smells sour, tastes bitter, or develops mold. Freezing can further prolong shelf life.

How long does Parmesan cheese last after best by date?

The printed “best by” date is simply an estimate of peak flavor and quality. When properly stored, unopened Parmesan lasts:

  • 2 weeks to 2 months past the best by date on wedges
  • 3-4 months past the date on grated Parmesan

Monitor refrigerated Parmesan carefully after its date, discarding if any mold, sliminess, or off-odors arise. Otherwise, good Parmesan is perfectly safe to consume.

Conclusion

With proper storage and handling, Parmesan cheese can maintain quality and flavor well beyond common expiration estimates. Keep Parmesan well-wrapped, refrigerated, and monitored for signs of spoilage. While it can last over a year if unopened, use opened Parmesan wedges within 2 months and grated Parmesan within 2-4 weeks for best taste and texture.

Knowing the shelf life, optimal storage methods, and signs of spoiled Parmesan can minimize waste and ensure you safely enjoy this popular hard Italian cheese to the very last crumble.

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