white spots on parmesan
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White Spots on Parmesan Cheese – What Does It Mean?

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When you see a speck of white on your food, it’s natural to assume mold has ruined your meal.

If you’ve had some parmesan waiting in your fridge for the perfect recipe, don’t immediately panic if you unwrap it to find it speckled with white. 

What are the white spots on parmesan cheese? White spots on parmesan cheese may be mold, but they may also be tyrosine or calcium lactate crystals that develop the flavor and fragrance of certain aged cheeses. If they are inside the cheese, they are likely crystals. If they are only on the outside and the cheese tastes off, they may be mold.

Understanding the difference between mold and crystals may save your day, or at least your dinner.

In this article, you’ll learn what cheese crystals are, how to tell them apart from white mold, and when and how to salvage parmesan instead of tossing it.

Parmesan vs Parmigiano Reggiano

If there are white spots on your parmesan, the first thing you need to figure out is whether you have imitation parmesan, which is the most common type of parmesan in North America, or if you have true Parmigiano Reggiano.

Parmesan is actually the copycat version of Parmigiano Reggiano. Real Parmigiano Reggiano must follow strict rules, regulations, and guidelines to be worthy of the title.

Here are a few of the qualifying factors:

  1. It must be made in Italy.
  2. It may have only 3 ingredients: milk, salt, and animal rennet.
  3. It must be aged at least 12 months.
  4. It must be approved by the regulatory board.
parmigiano reggiano

If your parmesan comes in a shelf-stable container, it is an imitation.

But even if it comes in a triangular block of hard, white cheese from the deli section of your grocery store, there is a higher than average chance it is still “parmesan,” not true Parmigiano Reggiano. 

The flavors of real versus imitation parmesan are significantly different when tasted side-by-side, but due to the price differential and the market saturation of imitation parmesan, many people have never even tasted the official cheese.

The reason it’s so important to know whether you have the real Italian hard cheese or an imitation variety is that white spots can mean entirely different things, depending on which one you have.

One way to tell the differences is to try and melt your parmesan, or a small piece of it. If it melts easily, it’s Parmigiano Reggiano. If it has a hard time melting down and separates, burns, or becomes stringy, it’s likely imitation parmesan.

Parmesan Cheese Mold

If you have the more common imitation parmesan, there is a higher likelihood that white spots on your cheese are mold rather than something fabulous, as we’ll discuss later. 

Many of the cheeses America calls “parmesan” contain additives, preservatives, flavorings, and a variety of other ingredients, or even cheeses.

These may either extend the lifespan of your cheese or shorten it, in comparison to true Parmigiano Reggiano.

Mold in Grated Parmesan Cheese

You may not have ever considered the fact that parmesan cheese goes bad, as it is a hard cheese and has a long shelf life, but just like any other dairy product, it does have its limits.

Grated parmesan cheese, whether it is real or imitation, is more likely to mold than a block of cheese. This is simply due to the surface area that is exposed to the air and humidity, and therefore bacteria. 

When cheese molds, it’s likely to turn blue, though it can present as white mold without any blue. White mold is very hard to see on previously grated cheese, so you’re more likely to taste it accidentally than see it.

Any blue spots are certain indications of mold.

It’s also useful to keep in mind that, if by chance your cheese does grow a little mold, it’s much easier to slice off the affected area of a hard block of cheese than it is to pick out all the small pieces within grated cheese.

Investing in a zester and a block of hard Parmigiano Reggiano is not only going to please your tastebuds, but it can actually be more cost-effective in the long run by reducing waste if you don’t use it very often.

Cheese Crystals

Not all foods that develop white spots are going bad. In fact, they can turn out to be a good sign for your culinary quests. For example, sweet potatoes can have white ooze or spots if they are particularly sweet.

While you may be predisposed to assume any white spots on cheese are mold, aged and true Parmigiano Reggiano may develop crystals, rather than mold, and this would actually be a very good thing.

As certain types of cheese age, the proteins break down in a way that creates inconsistencies in texture and flavor. There may be a bit of crunch to the texture and the flavor may taste especially sweet or savory.

There are two types of cheese crystals that can form in aged cheese but will not form in imitation parmesan: tyrosine crystals and/or calcium lactate.

Tyrosine Crystals on Cheese

Tyrosine is an amino acid that forms a crystalline shape as it builds up during the aging process of certain cheeses.

This type of bright white crystal forms inside the main block of cheese, but can be seen on the outside as well. They form, generally, wherever there are small eyes or tiny air pockets. They are very firm and crunchy.

They add more texture than flavor but tend to grace only the most flavorful of cheeses, so are often called flavor or salt crystals.

Calcium Lactate on Cheese

This type of crystal can be found either inside the cheese or on the surface. It’s a softer crystal and paler, blending in slightly better with the cheese itself.

Calcium lactate crystals form as the lactose in cheese breaks down through the aging process. Lactic acids are formed, which bind with calcium ions to form calcium lactate. 

Calcium lactate crystals are most likely to form where the cheese has been exposed to moisture, typically on the surface of the cheese. It looks more like a powdery smear of white than distinct white spots. 

The calcium lactate crystals themselves don’t change the taste of the cheese, but they are usually a sign of a well-aged block of parmesan that will have a robust flavor profile.

White Spots on Parmesan – Cheese Crystals or Mold?

How can you tell if the white spots on your cheese are crystals or mold? Your first clue is in the quality of the cheese.

A true Parmigiano-Reggiano is very likely to have crystals and very unlikely to develop mold because it’s a very low-moisture cheese. 

white spots on parmesan

The next indication is whether the spots are on the inside of the cheese or the outer layer. If they’re inside the cheese, they’re almost guaranteed to be crystals. This will add a pleasant burst of flavor to your already delicious parmesan.

If you’re still not sure, take a small taste. Even if it’s along the outside of your cheese, it may not be mold.

A small amount of mold isn’t likely to hurt you unless you have an allergic reaction to it, but it will give your tastebuds a chance to tell you whether the development is a good or bad addition to your cheese.

White Mold on Cheese

If you’re convinced that the white spots on your cheese are, indeed, mold, your next questions are most likely, “Is white mold on cheese dangerous? Should I toss it or try to salvage as much as I can?”

First, is your parmesan a block of cheese or grated? If it is grated, you’ll want to discard the entire container or package.

Unfortunately, it’s nearly impossible to remove white mold contamination from a collection of shredded cheese pieces, especially when the cheese itself is nearly the same color as the mold. 

Mold on cheese can support the growth of potentially dangerous bacteria including E. coli and salmonella, so it’s best not to take chances. 

If, however, you have a block of very hard parmesan that has mold on the surface, you can cut around the mold and salvage the rest of the cheese.

There is very little moisture in hard cheese, so any mold growth is likely due to exposure to external humidity and isn’t likely to be able to penetrate far into the cheese.

Cut at least a 1-inch radius around any mold and save the rest, carefully wrapping it to prevent any more moisture from attacking your cheese.

Related Questions

How Long Is Parmesan Aged?

Most commercial parmesan cheese isn’t true parmesan and doesn’t have a specific length of time that it must be aged, if at all.

True Parmigiano Reggiano, however, must be aged for a minimum of 12 months to pass inspection and gain approval.

Aging beyond 1 year is up to the discretion of the producer and it may be carefully aged to develop aroma, texture, and flavor for multiple years.

Different ages of cheese will be better suited for different dishes. A younger cheese is milkier, with brighter, almost fruity flavors. The older cheeses become more crumbly and develop a stronger umami flavor.

Is Parmesan Vegetarian?

Many vegetarians, though not all, consume cheese and cheese products regularly, but parmesan should not be one of the varieties included.

This is because parmesan is not strictly made from milk, but also uses animal rennet to set the cheese as it’s being made. 

Animal rennet is an enzyme found in the stomach lining of calves that helps them to digest lactose. This same enzyme causes the milk used for making cheese to coagulate, separating the curds from the whey.

Not all cheese is made with rennet, but parmesan is, unless specifically labeled otherwise. You can, however, find cheeses that are made with plant rennet.

Is the Parmesan Rind Edible?

Parmesan, specifically Parmigiano Reggiano, develops a hard rind as it ages, which protects the fresh cheese beneath it.

It technically is edible, but few people are interested in snacking on this tough, chewy crust, despite the strong parmesan flavor.

The best way to use your parmesan rind is to cook with it. They can be boiled to add flavor to a sauce, broth, or even grains or slow-cooked pasta.

Just be sure to remove what is left of the rind before serving. You can also place a strip of rind into olive oil to create parmesan-infused oil.

Up Next: Recipe – Parmesan Crusted Chicken With Mayo

One Comment

  1. Re the hard rind of real parmigiano… I have great success carefully microwaving it at max power, but looking on.
    It expands a lot and when done is an excellent “cheese puff”… 100% cheese, puff. 🙂

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