The Fast Mold Growth on Mozzarella Cheese: Causes and Prevention

  • Mozzarella molds faster due to its high moisture content and absence of preservatives, creating an environment conducive to mold growth
  • It should be stored in its original liquid (brine or whey) inside a sealed container in the refrigerator
  • The brine need not be changed unless it develops a bad odor, at which point a fresh saltwater solution should be prepared
  • Despite appearances, the orange color on mozzarella can be due to harmless bacteria, not necessarily mold
  • Mozzarella’s freshness and safety can be assessed by its texture, smell, and color, using caution if signs of spoilage are present

What Makes Mozzarella Cheese Go Moldy So Quickly?

A scene of making a new brine solution for mozzarella storage

You might have observed that mozzarella molds faster than other cheeses. Even when left unopened, mozzarella can develop an unappetizing orange hue, making it look quite unappealing.

It’s similar to other fresh cheeses, such as chèvre and ricotta.

Unlike firmer cheeses, mozzarella lacks preservatives. It is best stored in the liquid it comes with to maintain its freshness.

You have to be a romantic to invest yourself, your money, and your time in cheese – Anthony Bourdain

This liquid can be water, but it is typically brine or sometimes whey. For optimal storage, keep the mozzarella in an airtight container.

You don’t need to change the liquid unless it develops a strong, unpleasant odor. In that case, prepare a new brine solution with one tablespoon of salt per several cups of water.

Be cautious with the amount of salt, as it will affect the flavor of the mozzarella. Another reason mozzarella molds quickly is due to its status as a fresh cheese, not aged, with high moisture content.

Mold grows well in damp conditions. Pizza mozzarella differs slightly, having a lower moisture content and usually not stored in liquid.

It can be securely wrapped in plastic and will remain fresh for a few days.

Is the Mozzarella Moldy?

A scene showing pizza mozzarella wrapped securely in plastic

Of course, you are going to assume that if your mozzarella is a strange color, then it must be moldy.

And therefore, you can’t eat it.

However, that’s not necessarily the case.

When you think of mold on food, it’s usually a blue or green color with a furry texture.

But with soft cheeses and mozzarella, in particular, they usually turn orange.

Mozzarella has to be perfect and impeccably sourced or it’s like eating a blind whale’s eyeball – A.A. Gill

But, although it’s a form of mold, it is more accurately described as a bacteria and is harmless. 

Yes, it might taste a bit odd and look pretty weird on your pizza, but you can eat it!

The bacteria is called Brevibacterium linens and is found naturally in raw milk, which is how it gets into the mozzarella.

And then, the high moisture content of the cheese helps it spread. 

Some cheesemakers deliberately add bacteria to give the cheese a distinct color and flavor.

However, if your mozzarella has turned blue or green, then it should be discarded. 

Another sign that the mozzarella may be off is if the edges of it have gone hard. 

Mozzarella should be soft and squidgy, so any hardness is not a good sign.

Is Mozzarella Cheese Moldy?

My Final Thoughts

Mozzarella cheese molds faster because it is a soft cheese and has no preservatives.

The high moisture content makes mozzarella more susceptible to mold.

The brine in which it’s stored should keep it fresh, but the liquid may need to be replaced.

Despite its appearance, the mozzarella might not be moldy.

An orange color indicates the harmless presence of bacteria.

Let things taste the way they are – Alice Waters

At the end of the day, always use your judgment when deciding whether to eat the cheese or not!

But look out for another clue that the cheese might be off if the mozzarella has a fishy smell.

Does this information prompt you to reconsider or adjust how you handle and consume fresh cheeses like mozzarella in your daily cooking practices?

Let us know in the comments below!


A close-up view of mozzarella cheese showing signs of spoilage

Q: Why does mozzarella cheese mold faster than other cheeses?
A: Mozzarella molds faster because it is a fresh cheese with high moisture content and lacks preservatives, creating an ideal environment for mold growth.

Q: What makes mozzarella go moldy quickly?
A: Mozzarella’s lack of preservatives, its status as a fresh cheese, and its high moisture content make it susceptible to quick molding.

Q: How should mozzarella be stored to prevent molding?
A: Store mozzarella in its original liquid (water, brine, or whey) inside an airtight container. Changing the liquid is not necessary unless it smells strong and unpleasant.

Q: Can you eat mozzarella if it turns orange?
A: Yes, an orange color in mozzarella is usually due to harmless bacteria, not mold. However, if it turns blue or green, it should be discarded.

Q: What are signs that mozzarella cheese is off?
A: Mozzarella is likely off if it smells fishy or if the edges have gone hard, as fresh mozzarella should be soft and squidgy.

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