Is Blue Cheese Actually Mold, and Is It Good for You?

Medically Reviewed on 8/30/2022

What is blue cheese?

Blue, or blue-veined cheese, is identified by the growth of a certain type of mold that gives it a unique color and flavor. Blue cheese does contain mold, but it is not harmful.
Blue, or blue-veined cheese, is identified by the growth of a certain type of mold that gives it a unique color and flavor. Blue cheese does contain mold, but it is not harmful.

Blue, or blue-veined cheese, is identified by the growth of a certain type of mold that gives it a unique color and flavor. This article explains what blue cheese is made up of and whether you should eat it.

Blue cheese, also known as blue-veined cheese, is identified by the growth of blue lines (called veins) that are characteristic of this type of cheese. These blue veins occur due to the growth of a type of fungus called Penicillium roqueforti, which gives the cheese its particular color and taste.

Blue cheese is widely grown in several countries, with each having its traditional method of preparation. Depending on where the cheese is prepared, the methods involved use milk from different sources such as pasteurized cow’s milk (Italy and Sweden), raw ewes’ milk (France), and sometimes a mixture of milk from many animals, including cows, goats, and ewes (Greece).

The nutrient and moisture content of these cheeses depend on the method of preparation. These methods also give the cheese specific characteristics. Some of the most popular types of blue cheese include the Italian Gorgonzola, the French Roquefort, the British Stilton, and the Danish Danablu. 

Blue cheese has been in production for a very long time. Some of the earliest mentions of blue cheese date back to the year 879 AD, and Roquefort cheese was mentioned in a customs report in 1070 AD. This indicates that blue cheese has been around for centuries.

The distinct flavor of blue cheese is attributed to the breakdown of fat through a process called lipolysis that leads to the formation of fatty acids. The action of Penicillium roqueforti converts these fatty acids into a group of molecules called ketones that gives them a unique smell and flavor.

The smell of the cheese depends on the type of ketone produced by the mold after it breaks down the fatty acids. Some ketones and their aromas are listed below:

  • Propanone: Nail polish remover
  • Butanone: Paint thinner
  • Pentan-2-one, hexan-2-one, and heptan-2-one: Fruity or floral
  • Octan-2-one and decan-2-one: Earthy or fruity

Just as your body needs oxygen to stay alive and carry out critical functions, molds also need oxygen. When denied adequate oxygen, mold metabolism changes and can lead to unusual flavors and colors. That’s why you should never pack blue cheeses in a vacuum pack.

Does blue cheese contain mold?

Blue cheese is usually made due to the action of a microorganism called Penicillium roqueforti, which is a type of fungus. Fungi consist of two types of organisms – yeasts and molds. Penicillium roqueforti is a type of mold, so, technically speaking, blue cheese does contain mold.

Some types of mold produce chemicals called mycotoxins that are harmful to humans. Research has shown that many factors influence the growth of these mycotoxins. These include factors such as the local weather, contamination by pests, and inadequate cleanliness levels when the food is harvested or stored.

These harmful types of molds, though, typically grow on food that’s not been used for many days. On the other hand, the mold that is used to make blue cheese does not produce any harmful substances and is safe for human intake.

How to take care of blue cheese

There are several points at which contamination of cheese could occur. Sometimes, the cheese rind could be a possible source of contaminants that could move to the cheese slice when it’s cut, and mold can grow as the cheese is stored in your house. The brine that’s used to salt or cure the cheese could also contain fungi that could spoil the cheese.

If you notice that your cheese is spoiled, you should throw it away. While the presence of mold itself is not necessarily a cause for concern (at least in the case of blue cheese) make sure that you’ve taken the necessary precautions while storing it. Check the use-by date and make sure you use the cheese by then.

Eating blue cheese that’s gone bad could cause some problems. Some research has shown that eating spoiled cheese could lead to food poisoning and cause symptoms such as stomach cramps, vomiting, and diarrhea.

Certain strains of mold are known to produce mycotoxins that could lead to reduced immune function, digestive problems, and cancer. That’s why it’s very important to make sure you buy quality cheese.

Is it safe to eat blue cheese?

Blue cheese gets its name due to the blue veins caused by the growth of the mold Penicillium roqueforti. While certain types of mold produce toxic substances that could harm your health, the mold used to prepare blue cheese is not harmful. It simply gives the cheese a distinct flavor and aroma.

Blue cheese, which typically has a salty taste, is excellent when combined with a contrasting, sweet flavor such as that of port or sherry.  You can also try to complement the singular flavor of blue cheese with dry or fresh fruits like apples, cherries, dates, figs, and apricots.


Foods That Aren't as Healthy as You Think See Slideshow

Health Solutions From Our Sponsors

Medically Reviewed on 8/30/2022

Cantor, M. D., Tempel, T. V. D., Hansen, T. K., Ardo, Y. Cheese: Chemistry, Physics and Microbiology, Fourth Edition, Elsevier, 2017.

Centers for Disease Control and Prevention: "Foodborne Germs and Illnesses."

Cheese Science Toolkit: "Blue," "Microbes 101."

Harvard T. H. Chan School of Public Health: "Cheese."

Microorganisms: "Diversity and Control of Spoilage Fungi in Dairy Products: An Update."

Pediatrics and Child Health: "Foodborne infections."

Shokuhin Eiseigaku Zasshi, Journal of the Food Hygienic Society of Japan: "Examination of the taxonomic position of Penicillium strains used in blue cheese production based on the partial sequence of ß-tubulin."

Toxicological Research: "Prevalence of Mycotoxins and Their Consequences on Human Health."