Can Mozzarella Cheese Go Bad?

Last Updated on January 17, 2024 by Aaron

Mozzarella cheese is a delicious and versatile ingredient that can be used in many recipes. But, you shouldn’t buy more than you can use in a week because it can go bad.

In general for the expiration date, fresh mozzarella has a shelf life of roughly 5 days once opened. Loaf/block mozzarella can last for up to 21 days, and smoked mozzarella lasts up to 28 days once opened.

And it’s best to keep your cheese refrigerated and to use it before the expiration date. Mozzarella cheese can spoil easily, so it’s important to inspect it often for signs of spoilage. Signs of spoilage include a change in texture or taste, discoloration, mold growth, and an off smell. We will discuss more below.

Fresh mozzarella lasts up to a week

Fresh mozzarella will last 3-7 days once opened. It doesn’t last as long as other cheeses because its date is usually only about three to four weeks from the manufacture date. To keep fresh mozzarella lasting longer, you can store it in the fridge wrapped in plastic or submerged brine (replace every 2 days).

When wrapping mozzarella cheese in plastic, it’s important to make sure it’s sealed tight so it doesn’t dry out and harden. If the plastic is too loose, the cheese can get dry and hard more quicker. If you find your mozzarella cheese to be old and slightly sour, it’s still probably okay to eat as long as there is no mold or sign of spoilage. Eating sour mozzarella shouldn’t make you sick. However, if there is any visible mold or if the cheese smells bad, it’s best to discard it.

Mozzarella can also spoil if it’s exposed to too much heat or moisture. Mold can usually form on the surface of the cheese, and it’s important to watch for it. If you see any signs of mold, discard the cheese. It’s also important to note that some molds can be toxic, so it’s best not to take any risks and just throw away any cheese that has any visible mold.

While hard cheeses like cheddar and Swiss can usually have mold cut off and eat the rest, it’s not safe to do the same with soft cheeses. Soft cheeses like mozzarella, brie and camembert usually have more moisture and cutting off the moldy parts will not make the product safe for consumption. In fact, it can make the mold spread and make the cheese unsafe to eat.

Mozzarella blocks will last for 2-3 weeks

After being opened, the mozzarella sticks or loaves can last up to a month. The date on the label is usually around 2-3 months from when it was packaged, so if you don’t think you’ll be able to use it by then, buy less and store what you do have in the refrigerator. Keeping it in the refrigerator will help keep the mozzarella fresher for longer.

If you find that your mozzarella has hardened, don’t worry! Mozzarella is still fine for melting and works well in recipes where it will be melted anyway. It may just need to be softened up a bit first.

How to Know if Mozzarella Cheese is Bad

Mozzarella cheese can go bad if it’s not stored properly, or if there has been a change in temperature. It’s important to inspect it often for any signs of spoilage.

  • Unopened pack of mozzarella seems bloated

One indication that mozzarella cheese may have gone bad is if the pack is bloated or puffy. This happens when the cheese is exposed to air, and the bacteria has started to grow and release gases. You should discard this cheese immediately.

  • Visible mold on the exterior

This is a clear indication that the cheese is contaminated and spoiled. For example, green or black spots on the surface of mozzarella cheese is a sure sign that the cheese is no longer safe to consume.

If you find your mozzarella is having a patch of pink discoloration. It’s caused by a carotenoid-producing bacteria Thermus thermophilus, which is considered a common defect in the dairy industry. Even though there is no direct link to food safety thus far, if you find them unappetizing, discard the cheese.

  • Change texture – dried and harden (but still edible)

Some mozzarella cheese can get dry and hard, but it’s still safe to eat. It just might not taste as good as fresh mozzarella.

  • Yeasty sour feet-like smell, or an excessively cloudy brine.

Sometimes you will see floaters on the brine, those are mild solids. If doesn’t smell off or look like molds, it’s usually fine to eat but not at its best. If kept for too long, where the cheese can slowly dissolve a little bit in the brine, making it looks cloudy.


  1. Quigley, Lisa et al. “Thermus and the Pink Discoloration Defect in Cheese.” mSystems vol. 1,3 e00023-16. 14 Jun. 2016, doi:10.1128/mSystems.00023-16
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