Last updated: June 10, 2026.
Parmesan lasts longest as a tightly wrapped block kept cold and dry. Follow the package date first. After opening, a block of hard Parmesan can often keep for several weeks when handled cleanly, while grated or shredded Parmesan should be used sooner and discarded if it grows mold.
Quick Storage Table
| Parmesan type | Storage guidance | What to watch for |
|---|---|---|
| Unopened packaged Parmesan | Follow the package date and storage instructions | Do not use swollen, leaking, or moldy packages |
| Opened block or wedge | Wrap well, refrigerate, and use within several weeks for best quality | Dryness, off smell, heavy mold, or sliminess |
| Fresh grated or shredded Parmesan | Use sooner than a block and follow the label | Discard if mold appears |
| Shelf-stable grated Parmesan | Follow the label before and after opening | Moisture clumps, off smell, or mold |
| Frozen Parmesan | Possible, especially for grated cooking use | Texture can become drier and crumbly |
How To Store Parmesan
- Keep Parmesan refrigerated unless the package clearly says it is shelf-stable before opening.
- Wrap blocks in cheese paper, parchment plus loose plastic, or a breathable cheese bag.
- Keep grated Parmesan tightly covered and use a clean spoon.
- Label the opening date so you do not guess later.
- Keep Parmesan away from raw meat, seafood, and wet produce.
Can You Eat Parmesan With Mold?
For a firm block of hard cheese, USDA guidance allows cutting away a small mold spot by trimming at least 1 inch around and below the mold, keeping the knife out of the moldy area. Do not use this rule for shredded, grated, sliced, soft, or wet cheese. Discard those if mold appears.
Signs Parmesan Has Gone Bad
- Sour, rotten, or ammonia-like smell.
- Slime, wetness, or sticky surface.
- Heavy mold, mold spread through grated cheese, or mold plus bad smell.
- Swollen package or leaking liquid.
- Unknown opening date with quality changes.
Can You Freeze Parmesan?
Yes. Parmesan can be frozen, especially if you plan to grate it into soups, sauces, pasta, or casseroles. Freeze in small pieces or grated portions, wrap tightly, and expect a drier, more crumbly texture after thawing.
FAQ
Does Parmesan cheese need to be refrigerated?
Most opened Parmesan should be refrigerated. Shelf-stable grated products may have different label instructions before opening, but once opened you should follow the package storage directions.
How long does grated Parmesan last after opening?
Follow the package label. Grated and shredded Parmesan have more surface area than a block, so they usually lose quality faster and should be discarded if mold appears.
Can you cut mold off Parmesan?
Only for a firm block of hard cheese with a small mold spot. Cut at least 1 inch around and below the spot. Discard grated, shredded, sliced, soft, or wet cheese if mold appears.
Can old Parmesan make you sick?
It can if it is moldy in the wrong form, spoiled, contaminated, or stored improperly. Do not taste Parmesan to test it; discard it if the smell, texture, package, or mold pattern is concerning.