Parmesan Cheese: How Long Does It Really Last?

Dried Parmesan cheese is a versatile ingredient used in a variety of dishes, from pasta to pizza. Its shelf life is a common concern for many home cooks, especially since it is often sold with a best before date. Properly stored dried Parmesan can last for several months beyond its expiration date. This guide will explore the factors that influence how long dried Parmesan cheese lasts after its expiration date, providing essential insights for cooks and food enthusiasts alike.

Proper storage is key

To maximise the shelf life of unopened grated Parmesan cheese, it should be stored in a cool, dry area, at a temperature of between 32°F and 40°F (or below 4°C). Exposure to heat and humidity can cause the cheese to spoil quickly, so it should be kept away from direct sunlight and moisture. It is also important to ensure that the cheese is well-sealed to prevent it from drying out or absorbing odours from other foods in the refrigerator. An airtight container or a vacuum-sealed bag can help to maintain its moisture content and prevent unwanted odours from affecting the cheese.

Once the package of Parmesan has been opened, its shelf life depends on how well it is sealed and stored. Opened Parmesan should be consumed within one to two weeks for the best quality, but if stored correctly in an airtight container in the refrigerator, it can last for up to three to four weeks.

It is also important to check for signs of spoilage, such as mould growth, off odours, or changes in texture. If the cheese has a sour or rancid smell, a yellow or brown colour, or a slimy or gritty texture, it should be discarded.

Unopened vs opened

The longevity of dried Parmesan cheese differs depending on whether it is unopened or opened.

Unopened

Unopened dried Parmesan cheese can last for several months if stored properly in the refrigerator. The precise answer depends on the storage conditions. To maximise the shelf life, it should be kept in a cool, dry area. If stored at room temperature, unopened dried Parmesan cheese will generally stay at the best quality for about 12 to 18 months.

Opened

Once opened, dried Parmesan cheese should be consumed within a few weeks for the best quality. If stored correctly in an airtight container in the refrigerator, it can last for up to three to four weeks.

It is important to note that dried Parmesan cheese can go bad before the expiry date if it is not stored properly. To ensure the cheese lasts as long as possible, it must be stored in an airtight container in the refrigerator. This helps to prevent moisture and air from getting in, which can cause the cheese to spoil quickly. Additionally, the cheese should be kept away from strong-smelling foods as it can absorb their odours.

Packaging type

The packaging type is a key factor in determining how long dried Parmesan cheese will last after its expiration date. Proper storage is essential to maximise the shelf life of dried Parmesan cheese and prevent spoilage.

Commercially packaged grated Parmesan cheese, which is sold unrefrigerated, can generally be kept at best quality for about 12 to 18 months at normal room temperature. However, this assumes proper storage in a cool, dry area. Exposure to heat and humidity can cause the cheese to spoil quickly.

Once the package is opened, the shelf life of grated Parmesan cheese is significantly reduced. When stored in the refrigerator, grated Parmesan cheese can last for several weeks to a few months, depending on the quality of the cheese and storage conditions. To maximise its shelf life, it should be stored in an airtight container or resealable bag in the refrigerator. This helps to prevent moisture and air from getting in, maintaining the cheese's moisture content and preventing it from drying out or absorbing odours.

The type of airtight packaging can also make a difference. Cheese packaged in airtight containers can last longer than cheese in open containers, as it has less exposure to air. Additionally, it is important to keep the cheese away from strong-smelling foods, as Parmesan can absorb their odours.

It is worth noting that the use-by or expiration date on the package is not a safety date but rather the manufacturer's estimate of how long the cheese will remain at peak quality. The cheese can often be safely consumed beyond this date if it is properly stored, the package is undamaged, and there are no signs of spoilage, such as mould, off odours, or changes in texture or colour.

Signs of spoilage

The shelf life of dried Parmesan cheese can be extended by storing it in a cool, dry place, away from direct sunlight and moisture. Proper storage in an airtight container or resealable bag in the refrigerator can also prolong its freshness. However, it's important to regularly check for any signs of spoilage to ensure the cheese is still safe to consume. Here are some detailed signs of spoilage to look out for:

Mould

Mould growth is a common sign of spoilage in dried Parmesan cheese. If you notice any mould on the surface, discard the cheese immediately. Mould can cause food poisoning and other health issues, so it's not worth risking your health by consuming mouldy cheese.

Odour

An off odour is another indication that your dried Parmesan cheese has spoiled. If the cheese develops a sour, rancid, or ammonia-like smell, it's best to throw it out. Trust your nose—if it smells unpleasant or unusual, it's probably gone bad.

Texture

Changes in texture can also indicate spoilage. If your dried Parmesan cheese becomes slimy or gritty, it's likely spoiled and should be discarded. This change in texture can be a result of excess moisture or the growth of bacteria.

Colour

Discolouration is another visual sign that your dried Parmesan cheese has gone bad. If you notice any yellow or brown spots or patches on the cheese, it's best to get rid of it. This discolouration could be a result of oxidation or bacterial growth.

Taste

While it's not always advisable to taste-test questionable food, an unusual or unpleasant flavour can be a sign of spoilage. If you accidentally consume a small amount of dried Parmesan cheese and notice an off taste, such as a rancid or cardboard-like flavour, it's best to discard the rest of the cheese.

It's important to be vigilant and inspect your dried Parmesan cheese regularly for any of these signs of spoilage. By practising good food safety habits, you can reduce the risk of consuming spoiled cheese and avoid potential health risks, such as food poisoning.

Health risks of spoiled cheese

Dried Parmesan cheese, when stored properly, can last for several weeks to months past its expiration date. However, it's important to be vigilant about the signs of spoilage to avoid potential health risks. Here are the health risks associated with consuming spoiled Parmesan cheese:

Gastrointestinal Distress

Spoiled Parmesan cheese can cause gastrointestinal issues such as nausea, vomiting, diarrhoea, and abdominal pain. These symptoms can be unpleasant and may require medical attention.

Food Poisoning

Consuming spoiled Parmesan cheese can lead to food poisoning. Food poisoning is a serious condition that can cause nausea, vomiting, diarrhoea, and fever. In severe cases, it may even require hospitalization and, in rare instances, can be life-threatening.

Contamination

If Parmesan cheese has been exposed to other spoiled foods, it can become contaminated. This cross-contamination can lead to the growth of harmful bacteria, increasing the risk of foodborne illnesses.

Mould Growth

Mould is a clear indication of spoilage in Parmesan cheese. While it is generally safe to cut off the mouldy portion on hard cheeses, grated Parmesan cheese should be discarded entirely if mould is present. Mould can cause food poisoning and other health issues.

Discolouration and Texture Changes

Spoiled Parmesan cheese may exhibit discolouration, turning darker or paler from its typical golden hue. Additionally, the texture may become soft or crumbly instead of the usual firm and slightly grainy consistency. These changes indicate spoilage and can affect the taste and safety of the cheese.

Sour or Rancid Odour

A strong, sour, or rancid smell is a clear sign that the Parmesan cheese has gone bad. This odour indicates the presence of bacteria and spoilage, making the cheese unsafe for consumption.

Bitter Taste

Spoiled Parmesan cheese may have a bitter or unpleasant taste. This change in taste is a telltale sign of spoilage and can make the cheese unpalatable and potentially harmful.

To minimise the risk of health issues, it is crucial to store Parmesan cheese properly, follow expiration dates, and discard the cheese if any signs of spoilage are present.

Frequently asked questions