How you store mozzarella depends entirely on which type you have. Fresh mozzarella packed in liquid lasts about a week unopened and 3 to 5 days once opened, while low-moisture mozzarella (the firmer block or shredded kind) keeps for 3 to 4 weeks unopened and around 2 weeks after opening. The key difference: fresh mozzarella needs moisture to stay soft, and low-moisture mozzarella needs to stay dry and airtight.
Storing Fresh Mozzarella
Fresh mozzarella, the soft, white balls you find packed in liquid, should stay submerged in that liquid. The brine or whey it comes in keeps the curd soft, milky, and hydrated. Once you open the container, keep any leftover cheese in the same liquid, sealed in the fridge. If you simply wrap it in plastic without liquid, it dries out fast and you’ll want to eat it within 2 to 3 days. Submerged in brine or water, it holds up closer to a week.
If you’ve tossed the original liquid or need more, you can make a simple brine at home. Dissolve about 1 pound of non-iodized salt in 2 quarts of water. Add 2 tablespoons of white vinegar to bring the acidity down. This creates roughly an 18% brine solution, which matches the salinity cheesemakers use. Plain water works in a pinch for a day or two, but it will gradually leach salt and flavor from the cheese, making it bland and waterlogged.
Your fridge should be set between 38°F and 42°F for any mozzarella storage. Those are the USDA-specified temperatures for mozzarella cheeses. If your kitchen is cool and the cheese is well submerged in brine, leaving it out overnight is unlikely to cause problems, but refrigeration is the safer bet for anything beyond a few hours.
Storing Low-Moisture Mozzarella
Low-moisture mozzarella is the denser, firmer variety sold as blocks, slices, or logs. It comes vacuum-sealed or in shrink-wrapped packaging designed to lock out oxygen and hold in moisture. Those two goals, keeping air out and moisture in, are exactly what you need to replicate at home once you open the package.
After opening, wrap the cheese tightly in plastic wrap or place it in an airtight container. Press the wrap directly against the cut surfaces to minimize air exposure. Oxygen is what feeds mold and yeast on the surface, and exposed edges dry out quickly, developing a tough, rubbery rind. Stored this way, an opened block keeps for about 2 weeks. Unopened, it lasts 3 to 4 weeks in the fridge.
If you notice a small spot of surface mold on a block of low-moisture mozzarella, you can cut away the affected area with about an inch of margin around it. The dense, low-moisture interior is less hospitable to mold penetration than soft cheese. This doesn’t apply to fresh mozzarella or shredded cheese, where mold can spread invisibly through the higher moisture or loose pieces.
Storing Shredded Mozzarella
Pre-shredded mozzarella contains anti-caking agents like potato starch, cellulose powder, or calcium sulfate to keep the shreds from clumping together. These coatings slightly affect how the cheese melts but also help it stay loose in the bag. Once opened, squeeze out as much air as possible and seal the bag tightly, or transfer the shreds to an airtight container or zip-top bag.
Shredded cheese has far more surface area exposed to air than a solid block, which means it dries out and grows mold faster. Expect opened shredded mozzarella to last about a week, sometimes closer to two if you’re diligent about sealing. If you shred your own from a block, the shelf life is similar, but without the anti-caking agents the shreds will clump together. A light dusting of cornstarch can help if that bothers you.
Freezing Mozzarella
Mozzarella freezes well, and research on low-moisture mozzarella found no consistent, statistically significant change in firmness, texture, or flavor after a freeze-thaw cycle. That’s good news if you buy in bulk or want to extend the shelf life by months.
For blocks, wrap tightly in plastic wrap, then in a layer of aluminum foil or a freezer bag. For shredded mozzarella, freeze it in the original bag or portion it into freezer bags. Fresh mozzarella can be frozen, but it loses some of its delicate, creamy texture once thawed because the ice crystals disrupt its high-moisture structure. Thawed fresh mozzarella is better suited to cooked dishes like pizza or baked pasta than a caprese salad.
Thaw frozen mozzarella in the refrigerator, not at room temperature. A 2.5-kilogram loaf takes roughly 5 hours to pass through the critical temperature zone during thawing, so smaller home portions will thaw faster, typically overnight in the fridge. Once thawed, the cheese may soften slightly over the following days, which is a normal aging effect accelerated by the freeze-thaw process. Use thawed mozzarella within a week or two, and don’t refreeze it.
How to Tell if Mozzarella Has Gone Bad
Fresh mozzarella that has turned will smell sour or unusually sharp compared to its normally mild, milky scent. The liquid it sits in may turn cloudy or develop an off smell. If the cheese feels slimy on the surface rather than smooth and slightly wet, that’s bacterial growth. Any pink, blue, green, or black patches of fuzz mean the cheese should be discarded entirely.
Low-moisture mozzarella spoils more slowly, but the signs are similar: an intensified, sharp smell that goes well beyond what you’re used to, visible mold in multiple colors or textures, or a surface that has become slimy or sticky. A small amount of surface drying or hardening at cut edges is normal and can be trimmed. But if the cheese has changed significantly in color or developed an ammonia-like odor, it’s past its useful life.
Quick Reference by Type
- Fresh mozzarella, unopened: Up to 1 week past the printed date, refrigerated in its liquid
- Fresh mozzarella, opened: 3 to 5 days submerged in brine; 2 to 3 days if wrapped in plastic
- Low-moisture block or sliced, unopened: 3 to 4 weeks refrigerated
- Low-moisture block or sliced, opened: About 2 weeks, tightly wrapped or in an airtight container
- Shredded mozzarella, opened: 1 to 2 weeks in a sealed bag with air pressed out
- Any mozzarella, frozen: Up to 6 months in the freezer; best used in cooked dishes after thawing