Which Molds are Toxic?


Simply put, mycotoxins are a toxic substance produced by a fungus and especially in mold.

As defined on by the National Institutes of Health (NIH),  Which Molds are Toxic - 4-Word Bound

“Mycotoxins are secondary metabolites produced by microfungi that are capable of causing disease and death in humans and other animals. Because of their pharmacological activity, some mycotoxins or mycotoxin derivatives have found use as antibiotics, growth promotants, and other kinds of drugs; still others have been implicated as chemical warfare agents. This review focuses on the most important ones associated with human and veterinary diseases, including aflatoxin, citrinin, ergot akaloids, fumonisins, ochratoxin A, patulin, trichothecenes, and zearalenone.”

An article published on the subject on Wikipedia offers this definition:

“A mycotoxin (from the Greek mykes, “fungus” and toxikon, “poison”) is a toxic secondary metabolite produced by organisms of the fungus kingdom and is capable of causing disease and death in both humans and other animals. The term mcotoxin is usually reserved for the toxic chemical products produced by fungi that readily colonize crops. One mold species may produce many different mycotoxins, and several species may produce the same mycotoxin.”

To date, no other cause of Mycotoxins has been recorded.


Mycotoxins Hazardous to Human Health

Essentially, all mycotoxins can be hazardous to human health. Five mycotoxins are most common:


Aflatoxins are a type of mycotoxin produced by Aspergillus, a species of fungi such as A. flavus and A. parasiticus. “Aflatoxin” is a classification of four different types of mycotoxins produced: B1, B2, G1 and G2. The most toxic of these is Aflatoxin B1, a very powerful carcinogen. It has been directly connected to harmful health effects, such as liver cancer, in many animal species. Aflatoxins are typically produced in tropical and subtropical environments. They have been linked to cotton, peanuts, spices, pistachios, and maize.


Ochratoxins are produced by Penicillium and Aspergillus species. There are three secondary metabolite forms, which are different in this way:

  1. Ochratoxin B (OTB) is a non-chlorinated form of Ochratoxin A (OTA).
  2. Ochratoxin C (OTC) is an ethyl ester derived from Ochratoxin A.

Aspergillus ochraceus is a contaminant that is found in a broad range of commodities, including such beverages as beer and wine. Aspergillus carbonariusis the primary mycotoxin found on vine fruit. Its toxin is typically released during the juice making process. Ochratoxin A has been identified as a carcinogen and a nephrotoxin. It has been tied to urinary tract tumors. However, research on its effects in humans has been limited due to “confounding factors.”


Citrinin is a toxin that was originally found in Penicillium citrinum. Since that time, it has been found in a number of species of Penicillium and a few species of Aspergillus. Some of these species are used in the production of some human foods, including cheese (Penicillum camemberti), Sake, Miso, and Soy Sauce (Aspergillus oryzae)Citrinin has been connected with yellowed rice disease in Japan. It also has been shown to act as a nephrotoxin in all species of animals tested. It has been associated with a number of human foods (including rice corn, wheat, barley, oats, rye, and food colored with the Monascus pigment. Yet its role in human health remains only partially understood. It can also interact with Ochratoxin A to depress RNA synthesis in murine kidneys.

Ergot Alkaloids

Ergot Alkaloids are compounds that form as a toxic mixture of alkaloids in the sclerotia of species of Claviceps. These are common pathogens found in several grass species. They are ingested from infected cereals (most often in the form of bread produced from contaminated flour. They cause ergotism, a disease historically called St. Anthony’s Fire. It appears in two forms. The gangrenous form affects blood suppl to the extremities. The convulsive form affects the nervous system. The presence of ergotism in humans has been reduced significantly by modern methods of cleaning grain. However, it is still a significant problem in veterinary medicine. Ergot alkaloids have been used in making medications.


Patulin is a toxin produced by the P. expansum, Aspergillus Penicillium, and Paecilomyces species of fungi. P. expansum is particularly prevalent in a number of moldy fruits and vegetables. It is very common in rotting apples and figs. It is destroyed during the fermentation processes, which removes it from apple drinks (cider, for example). There has been no demonstration that it is a human carcinogen. It has, however, been reported as a cause of damage to the immune system in some animals. In 2004, the European Community established limits on the concentrations of patulin in food items.


Fusarium toxins are produced by more than 50 species of Fusarium. They have been demonstrated to infect the grain of developing cereals (wheat and maize). Fusarium species include a spectrum of mycotoxins, including the fumonisins, which affects the nervous systems of horses and may cause cancer in rodents. The trichothecenes are most strongly connected with chronic and fatal toxic effects in humans and animals. Other major types of Fusarium toxins include beauvercin and enniatins, butanolide, equisetin, and fusarins.

The most common Indoor Molds

  • Aspergillus (all speces)
  • Cladospporium
  • Penicillium
  • Alternaria
  • Sraabachi chacarauim