You found a block of cheddar in the back of the fridge with some white spots on it. Or there is a bag of shredded cheddar that has been open for two weeks and you are not sure if it is still good. Or you spotted what looks like mold on the corner of the block and are wondering whether to cut it off or throw the whole thing out. Does cheddar cheese go bad?
The short answer: Yes, cheddar goes bad, but the rules are different depending on which form you have. Block cheddar lasts 3 to 4 weeks opened. Shredded cheddar lasts only 5 to 7 days. Those white spots are almost certainly not mold. They are calcium lactate crystals, completely normal and safe. And if you do find actual mold on a block of hard cheddar, USDA guidance says you can cut at least one inch around and below it and eat the rest.
For a full overview of how dairy and perishable foods compare on shelf life, visit our Complete Food Storage Guide.
Key Takeaways
Block cheddar (opened): 3 to 4 weeks refrigerated per USDA. Unopened: up to 6 months.
Shredded cheddar (opened): 5 to 7 days only. Increased surface area means faster spoilage.
Deli-sliced cheddar (opened): 3 to 5 days maximum.
White spots on aged cheddar are NOT mold. They are calcium lactate crystals, a natural byproduct of aging that is completely safe to eat.
Mold on block cheddar: cut at least 1 inch around and below the spot per USDA. Use a clean knife that does not touch the mold.
Mold on shredded or sliced cheddar: discard the entire package immediately. No exceptions.
Cheddar freezes for up to 6 months but becomes crumbly. Best used in cooked dishes after freezing.
How Long Does Cheddar Cheese Last?
The form cheddar is in when you open it determines almost everything about its shelf life. Block cheddar has far less surface area exposed to air and bacteria than shredded or sliced. That single difference creates dramatically different timelines.
Form
Unopened (Refrigerated)
Opened (Refrigerated)
Frozen
Block cheddar
Up to 6 months
3 to 4 weeks
Up to 6 months
Shredded cheddar (pre-packaged)
Use by printed date
5 to 7 days
Up to 6 months
Deli-sliced cheddar
Use by printed date
3 to 5 days
Up to 6 months
Freshly shredded from block
Not applicable
5 to 7 days
Up to 6 months
Block cheddar shelf life per USDA guidance. Opened hard cheese: 3 to 4 weeks per USDA. Always check for spoilage signs before using regardless of date. Consistent with USDA FoodKeeper guidance for hard cheeses.
White Spots on Cheddar: Not Mold
Calcium Lactate Crystals: Safe and Normal
One of the most common reasons people throw out perfectly good cheddar is the appearance of white spots, a white dusty film, or white patches on the surface or interior of aged cheddar. These are almost never mold. They are calcium lactate crystals, a natural byproduct of the aging process.
As cheddar ages, lactic acid combines with calcium in the cheese to form calcium lactate, which can crystallize on the surface or throughout the interior. The older and s
