Dairy
Hard cheese, block or grated

Parmesan CheeseShelf Life, Storage, and Spoilage Guide

Sourced from
USDA FoodSafety.gov

Pantry

Not Recommended

Unsafe once opened

Hard cheese should be refrigerated once opened. Unopened, while some hard cheeses are shelf-stable, refrigeration is recommended for optimal quality and to extend shelf life.

Refrigerator

Opened: 3-4 weeks; Unopened: 6 months

Store tightly wrapped in plastic wrap or aluminum foil, or in an airtight container, in the coldest part of the refrigerator. For grated Parmesan, keep in an airtight container.

Freezer

3-6 months

For best quality, freeze in blocks or shredded. Wrap tightly in plastic wrap, then in aluminum foil, or place in a heavy-duty freezer bag. Freezing may alter texture, making it more crumbly.

Signs of Spoilage

  • Visible mold (beyond surface mold on hard cheese that can be cut off)
  • Off-odor (sour, ammonia-like, or unpleasant smell)
  • Slimy or sticky texture
  • Significant discoloration

Room Temperature Safety

The 2-hour rule applies: Perishable foods, including cheese, should not be left at room temperature for more than 2 hours. If the ambient temperature is above 90°F (32°C), the limit is 1 hour.

The 'Danger Zone' for bacterial growth is between 40°F (4°C) and 140°F (60°C).

To minimize bacterial growth, always refrigerate Parmesan cheese promptly. Discard any cheese left in the danger zone for longer than the recommended time.

Expert Tips

Safe Handling

1

Always keep Parmesan cheese refrigerated once opened.

2

If mold appears on hard cheese, cut off at least 1 inch around and below the mold spot. Do not use the knife to cut into the clean cheese. Discard if mold is widespread or if it's a soft cheese.

3

Avoid cross-contamination by using clean utensils and cutting boards.

4

Do not leave cheese at room temperature for more than 2 hours (1 hour if temperature is above 90°F/32°C).

Related Items

Comparisons

Cheddar Cheese (hard, opened)Similar storage for other hard cheeses.
Fridge
3-4 weeks
Freezer
3-6 months
Swiss Cheese (hard, opened)Similar storage for other hard cheeses.
Fridge
3-4 weeks
Freezer
3-6 months
Soft Cheeses (e.g., Brie, Cream Cheese, opened)Soft cheeses have a much shorter shelf life and generally do not freeze well.
Fridge
1-2 weeks
Freezer
Not recommended