Mozzarella's Dark Side: When Good Cheese Goes Bad

Mozzarella cheese is a delicate, fresh cheese with a short shelf life. Properly stored, it will last about 1 to 2 weeks in the refrigerator. Once opened, it should be consumed within 3 to 7 days. If you're unsure whether your mozzarella has gone bad, there are several signs of spoilage to look out for, including mould, a sour smell, and a bitter taste. If you spot any of these, it's best to discard the cheese. However, if your mozzarella has simply started to harden or turn dry, it's still safe to eat—just cut off the dry parts before consuming.

How to store mozzarella cheese

Mozzarella is a soft, mild-tasting cheese that should be served as fresh as possible and therefore bought in small quantities.

Storing Fresh Mozzarella

If your fresh mozzarella comes in an airtight container with liquid, keep it in this container in the fridge to keep it moist. The liquid is actually whey, a byproduct of when mozzarella is made. You can replace it with water if it gets low. If your mozzarella was vacuum-packed, transfer it to a bowl of cold water, changing the water daily.

Fresh mozzarella will stay fresh for up to five days in the fridge if stored properly. It's best to eat it as soon as possible for the best taste and freshness.

Never freeze fresh mozzarella, as this will change the texture and flavour.

Storing Loaf and Shredded Mozzarella

Loaf mozzarella usually comes vacuum-packed. Once opened, wrap it in plastic wrap to prevent air contact and stop it from hardening.

If your shredded mozzarella came in a resealable bag or tub, make sure to seal it after opening. If it didn't, put it in an airtight bag or container.

Keep both types of mozzarella in the crisper drawer of your fridge, which has a different humidity level than the rest of the fridge, to prevent the cheese from drying out.

Loaf and shredded mozzarella can be kept for 21-28 days after opening.

Storing Unopened Mozzarella

You can store unopened mozzarella in the freezer for up to three months. Then, thaw it in the fridge for a day before using it.

How to Know if Mozzarella Has Gone Bad

If your mozzarella smells like sour milk, it has gone bad and should be thrown away.

Signs of spoilage

Fresh mozzarella is one of the few types of cheese that is packaged in liquid. This liquid can be either water or brine (water and salt).

The first sign that your mozzarella has gone bad is a bloated bag. If unopened, this is a clear indication that the cheese has spoiled.

Visible mould is another obvious sign that mozzarella has gone bad. If you see mould on a drier variety of mozzarella, it is possible to cut it off and use the remaining cheese, as long as it doesn't smell. However, it is important to note that moist cheeses like mozzarella can harbour harmful bacteria such as Listeria, E coli, brucella, and salmonella, so if you are in doubt, it is best to throw it out.

A sour smell is another indication that your mozzarella has gone bad. If either the cheese or the liquid it is stored in smells like sour cream, it is time to discard it. A similar rule applies to taste; if your mozzarella tastes sour or bitter, it has likely gone bad.

If your mozzarella has started to harden or turn dry, it is probably still safe to eat, as long as there is no mould. However, the dry parts will not taste very good, so it is best to cut them off and enjoy the rest of the cheese.

Finally, if your opened mozzarella has been sitting in the fridge for more than 10 to 14 days, it is best to get rid of it, even if it seems fine.

What to do if there's mould on the cheese

If you spot mould on your mozzarella cheese, the best course of action is to discard the entire product. While it may be tempting to simply cut off the mouldy part and salvage the rest, this is not advisable as it can be dangerous to your health. Mozzarella is a moist cheese, which means it can harbour harmful bacteria such as Listeria, E. coli, brucella, and salmonella. Therefore, if you see any visible mould, it's best to play it safe and throw the cheese away.

To prevent mould from forming in the first place, proper storage is key. Fresh mozzarella should always be kept refrigerated, whether it's unopened or opened. If you have an unopened package of mozzarella, the simplest way to store it is to leave it in its original packaging and place it in the refrigerator. It will stay fresh for a couple of days past the "best before" date.

Once the package is opened, you have a few options for storing the leftovers. One option is to wrap the cheese tightly in plastic wrap, making sure there are no air pockets. This will prevent the cheese from drying out and it should retain its quality for a couple of days. If you don't like using plastic wrap, you can use a reusable freezer bag instead. Just keep in mind that the cheese won't be wrapped as well and may not last as long.

Another option for storing opened mozzarella is to submerge it in liquid. Fresh mozzarella is usually packaged in either water or brine (water and salt). To replicate this, you can prepare a brine solution by using about one teaspoon of salt for every cup of water. Submerge the mozzarella in the brine or water, seal the container, and store it in the fridge. Be sure to replace the liquid every day or two. This method will give you a couple of extra days of storage time.

If you want to extend the shelf life of your mozzarella even further, you can freeze it. Cut the cheese into portions no larger than half a pound each, and wrap them tightly in heavy-duty aluminium foil or plastic freezer wrap, or place them in a heavy-duty freezer bag. Frozen mozzarella will maintain its best quality for about six months, but it can be safely stored indefinitely. When you're ready to use it, thaw the cheese in the refrigerator and it will keep for an additional 3 to 4 days. Frozen cheese may become crumbly and lose some of its flavour, so it's best suited for cooked dishes like sauces, soups, and casseroles.

How long mozzarella cheese lasts in the freezer

Mozzarella cheese is a versatile and delicious ingredient, but it's important to store it properly to maintain its freshness and flavour. Freezing is a great way to extend the shelf life of mozzarella cheese, especially if you have bought in bulk or have unused portions that you want to save for later.

When it comes to how long mozzarella cheese lasts in the freezer, the good news is that it can be stored indefinitely at a constant temperature of 0°F. However, the optimal period for the best quality is about six months. Beyond this period, the cheese may start to lose some of its flavour and texture. Frozen cheese may become crumbly and is best suited for cooked dishes, such as sauces, soups, and casseroles, rather than fresh dishes like salads.

To freeze fresh mozzarella cheese, cut the cheese into portions no larger than half a pound each. Then, wrap the portions tightly in heavy-duty aluminium foil or plastic freezer wrap, or place them inside a heavy-duty freezer bag. Make sure to label the packages with the date, so you can keep track of how long they have been in the freezer.

Once you are ready to use the frozen mozzarella cheese, you can defrost it in the refrigerator, in the microwave, or in cold water. If you thaw the cheese in the refrigerator, it can be kept for an additional 3 to 4 days before using it. However, if you use the microwave or cold water methods, the cheese should be consumed immediately.

How to tell if mozzarella cheese is bad

Fresh mozzarella is one of the few types of cheese that is packaged in liquid. This liquid can be either water or brine (water and salt).

The best way to store fresh mozzarella is to keep it in its original packaging and store it in the refrigerator. If you have opened the packaging, you can keep the mozzarella in its liquid, or wrap it tightly in plastic wrap or a reusable freezer bag. If you choose to store it in liquid, make sure to replace the liquid every couple of days.

Fresh mozzarella will typically last about 1 to 2 weeks in the refrigerator. If you want to keep it for longer, you can freeze it.

• The bag is bloated
• There is visible mould on the cheese
• The cheese or its liquid smells sour or like smelly feet
• The cheese has a sour or bitter taste
• The cheese has started to harden or turn dry

Frequently asked questions