Blue cheese is a common type of cheese that’s known for its strong smell and distinct flavor.

Although most people have tried blue cheese, many are unfamiliar with how it’s made and whether it can go bad.

This article takes a closer look at what blue cheese is, how it’s made, and whether it’s safe to eat moldy blue cheese.

Blue cheese is atype of cheesemade using cultures ofPenicillium, a type of mold.

Certain types of mold produce compounds called mycotoxins, which are considered toxic to humans ( 1 ).

These mold spores can grow on foods due to spoilage, and they’re typically fuzzy and white, green, black, blue, or grey ( 2 ).

However, unlike these types of mold, the varieties ofPenicilliumused to produce blue cheese don’t produce toxins and are considered safe to consume ( 3 ).

During the cheesemaking process,Penicilliumis added after the curds have been drained and rolled into wheels. The blue cheese is then left to age for 2–3 months before it’s ready to enjoy.

Penicilliumis responsible for the distinct taste and smell of blue cheese, along with its signature blue and green veins and spots ( 4 ).

summary

Blue cheese is made usingPenicillium, a type of mold that’s responsible for its unique taste, smell, and appearance. Unlike other types of mold, Penicillium does not produce toxins and is safe to consume.

Like other types of cheese, blue cheese can go bad if it’s not properly stored.

Therefore, it’s important to store blue cheese tightly wrapped in the refrigerator.

If stored properly, blue cheese can last 3–4 weeks in the refrigerator.

You can alsofreeze blue cheeseto help extend its shelf life even further.

Although freezing blue cheese may slightly alter its texture and appearance, it remains safe indefinitely when frozen.

summary

Blue cheese can go bad if it’s not stored properly. If wrapped and refrigerated, blue cheese can last 3–4 weeks. Frozen blue cheese can last indefinitely, although freezing it may slightly alter its texture and appearance.

If you notice anysigns of spoilageon your blue cheese, you should discard it immediately.

In particular, fuzzy white, green, pink, or grey spots growing on the surface of blue cheese may indicate that it has gone bad.

Additionally, cheese that develops a strong odor similar to ammonia may be spoiled.

Consuming spoiled blue cheese can cause food poisoning, which causes symptoms like nausea, vomiting, diarrhea, and stomach cramps ( 5 , 6 ).

Certaintypes of moldalso produce mycotoxins, which are toxic compounds that can suppress immune function, cause digestive distress, and even contribute to cancer ( 1 ).

Storing blue cheese properly and practicing food safety is the best way to prevent these negative side effects and enjoy blue cheese safely.

summary

Blue cheese should be discarded if there are any changes in its appearance or smell. Consuming spoiled blue cheese can cause food poisoning and increase exposure to harmful mycotoxins.

Blue cheeseis made using a type of mold calledPenicillium, which is responsible for its distinct taste, smell, and appearance.

Unlike other types of mold, the types ofPenicilliumused to produce blue cheese do not produce mycotoxins and are considered safe to consume.

However, blue cheese can still go bad, so it’s important to practice basic food safety practices and store blue cheese properly.