How long is grated parmesan cheese good for after opened?

In this brief guide, we will answer the question, ‘How long is grated parmesan cheese good for after opened?’. We will look at ways to store grated parmesan cheese. We will explore the causes that make grated parmesan spoil quicker.

How long is grated parmesan cheese good for after opened?

Parmesan cheese lasts long if they are in their sealed package. Vacuum packaging ensures that no environmental contaminants enter the packet but, they still have to be refrigerated. 

Grated parmesan cheese has both variants; refrigerated and shelf-stable.

One wise thing to do is not open up the packet until you are ready to use it. Then, wrap it tightly and store it in the fridge, regardless of whether you picked it up from the shelf or fridge, at the store.

When you use the cheese, scoop it up using a clean spoon. If you use one that is dirty or your hand, you are introducing bacteria to the bulk.

Grated parmesan lasts for quite a short time when compared to block or wedge. Grated parmesan lasts for two days in the fridge once the packet has opened. 

If you want to stretch the life of your grated parmesan, you may need to freeze it. 

Your parmesan is safe for 1-2 months if you bought a chunk. Opened parmesan might be fresh and delicious for more than two months if you followed the handling guidelines. However, parmesan’s grated counterpart last for only a fraction of that time.

If you bought the grated parmesan from the fridge, it would last anywhere from 3 to 6 days. Take extra caution such as protecting it from the air, keeping it tightly sealed, and keeping it refrigerated at all times.

Grated cheese and foods, in general, have a diminished shelf-life. Even though desirable because of easy handling; and can be sprinkled with ease but they come at a cost. Shredded or grated cheese of any kind spoils twice as quickly.

A greater surface area and tiny individual pieces mean they are more vulnerable. 

The air comes in contact with more of the cheese’s surface, and so do the bacteria. As more chunks or molecules of the cheese are exposed, they are susceptible to spoilage as well.

If you bought a block of it, the microbes do not penetrate through. The moldy exterior of spoiled cheese needs to be cut-off if it starts to spoil. The rest of it is edible and safe for consumption.

Fat Oxidation occurs in cheese, which makes the flavor rancid. However, the bacteria that spoil cheeses are listeria, brucella, salmonella, and E. coli. Hard cheeses like parmesan have a low moisture content and pH, which explains the longer shelf-life compared to some other cheeses. Coliforms and clostridium cause spoilage by releasing gas. However, molds contribute more to the spoilage process of cheese.

Other FAQs about Parmesan which you may be interested in.

Can you melt parmesan cheese?

Does parmesan cheese go bad?

How to safely store grated parmesan cheese?

You can freeze the grated parmesan if you like; it would extend the shelf-life up to 2 weeks. Put the grated parmesan in an air-tight container or heavy-duty freezer bag and store it. 

Do not leave grated parmesan out of the fridge for more than 2 hours. Unused grated cheese must be left in its original container and seal it shut tightly.

If you want a parmesan that lasts longer, pick it up from the shelf aisle. The grated cheese that is shelf-stable comes in a can that has an expiration of a year. After it opens, it needs to be in the fridge, where it will last for at least a couple of months. 

The parmesan that comes in a can is usually dehydrated. The moisture has to be drawn out by a drying process that caused the shelf life to increases. Moisture content is the impacting factor of food shelf-life. The higher the water content of the food, the quicker it spoils.

Dehydrated parmesan has a low water activity and, consequently, bacterial growth and spoilage delay for a significant time.

How to tell whether parmesan is still good?

Like other cheeses, parmesan grows mold as it spoils. It will also smell rancid and sour and, the color turns darker. 

 The color of parmesan is off-white, which leans toward yellow as it spoils. A change in texture also occurs in grated parmesan cheese. When you touch it, it will feel soft and wet. 

If you spot spoilage in grated parmesan, you may need to throw all of it. 

Even though parmesan categorizes as a hard cheese that does not spoil quickly, the phenomenon takes a toll after being shredded and, the spoilage accelerates. 

In this brief guide, we answered the question, ‘How long is grated parmesan cheese good for after opened?’. We looked at ways to store grated parmesan cheese. We explored the causes that make grated parmesan spoil quicker.


Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.