How to Tell If Blue Cheese Has Spoiled

Blue cheese has a strong flavor and aroma.

Although most people have had blue cheese, many are unaware of how it is made or if it has spoiled.

Blue cheese, like any other cheese, can go bad, and understanding how to recognize it is an important part of consuming cheese.

However, blue cheese is produced with Penicillium, which is a type of mold.

Certain molds produce substances known as mycotoxins, which are hazardous to human health (1).

These molds, which are often fuzzy and white, green, black, blue, or grey, can form on foods due to spoiling (2).

However, unlike these molds, the Penicillium mold used to make blue cheese does not release toxins and is safe to ingest (3).

Penicillium is added to the cheese-making process after the curds have been drained and rolled into wheels.

They then age the blue cheese for 3 months before it is ready to eat.

Penicillium gives the blue cheese a unique taste and smell, as well as its distinctive blue and green veins and dots (4).

Inspecting the Cheese

The first thing to do to check your blue cheese is to smell it. Fresh blue cheese has a distinct aroma, but it changes as it ages.

Usually, if the blue cheese has gone bad, it will smell like ammonia. It’s a good idea to give the blue cheese a whiff when you first get it home.

You’ll be able to tell when the aroma changes if you know what it smells like when it’s new. Mold, which is often blue or green in appearance, is already present in fresh blue cheese.

You should, however, pay attention to the color of the creamy section of the cheese, which is usually white, beige, or yellow.

If your blue cheese has turned pink, brown, or green, it has probably spoiled. Food poisoning can result from consuming spoiled blue cheese, which produces symptoms such as nausea, vomiting, diarrhea, and stomach cramps (5, 6).

Just like the scent of the cheese, also make a note of the color. When it’s new, you can identify changes if it goes bad.

Besides color changes, inspect the cheese to see whether the surface is slimy or fuzzy, and discard if you notice texture changes.

If your blue cheese still smells and looks the same, you can typically determine if it’s gone bad by tasting it.

While fresh blue cheese has a powerful, sharp flavor, as it spoils, it becomes very unpleasant. If you try a piece of blue cheese and it’s too strong to eat, throw it away.

In most cases, tasting a slight amount of spoiled blue cheese will not make you sick, so you can spit it out if it has spoiled.

Reminding Expiry Date

You should refrigerate blue cheese to keep it fresh; therefore, leaving it out on the counter will cause it to spoil faster. Always check the expiration date on your cheese.

In most cases, it will not spoil for up to four weeks after the date. Make sure your refrigerator temperature is below 40 degrees to preserve your blue cheese as fresh as possible.

Most of the time, you’ll notice that it’s gone bad within a few days if you’ve left your blue cheese out of the refrigerator, and it’s better to discard it.

You can store blue cheese in the freezer for a long time by maintaining the freezer at 0 degrees (7).

However, for the best taste and texture, don’t store it frozen. Keep in mind that if you store blue cheese for longer, the flavor and texture can alter.

It loses some of its pungency and breaks more easily.

How to Store Blue Cheese?

To store your blue cheese in the freezer, cut it into chunks and divide it by its equivalent weight.

Wrap each piece with parchment paper before keeping it in the refrigerator or freezer.

The next step is to wrap the paper in plastic wrap or foil to keep it from drying out. If you’re freezing the cheese, put the double-wrapped in a plastic freezer bag to keep it from getting freezer burnt.

For example, when you freeze the cheese, small ice crystals grow on the interior, damaging the internal structure. When it thaws, water is released, causing the product to dry up, crumble, and possibly develop a crumbly texture (8, 9).

If you think the cheese is absorbing the flavors of other products in your refrigerator, store it in an airtight container after wrapping.

The colder the blue cheese, the longer it will keep its freshness. However, the bottom of the fridge is the coolest place to keep it fresh for as long as possible.


The aroma of fresh blue cheese is unmistakable, but it changes as it ages.

If the blue cheese has gone bad, it will usually smell like ammonia.

Consuming rotten blue cheese can cause food poisoning.

Blue cheese is created with a mold called Penicillium, which gives it its taste, aroma, and look.

Unlike other types of mold, the Penicillium mold does not create mycotoxins and is deemed safe to consume.

However, blue cheese can go bad, so it’s critical to follow basic food safety precautions and preserve blue cheese carefully.

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