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Mold on consumer products: How dangerous is it?

Clara Chan, MSc, DABT

May 18, 2018

A major home furnishing store recently recalled about 175,000 comforters “due to risk of mold exposure.” The recall was reportedly made “after a few mold spores were detected on a minimal number of units.”1 In the US, other consumer products have been recalled “due to risk of mold exposure.” The recall notices state that mold “can be present” on the products, “posing a risk of respiratory or other infections in consumers with compromised immune systems, damaged lungs or an allergy to mold.”2

In reality, mold spores are present everywhere, and it is normal to have mold spores on surfaces and furnishings in the indoor environment. Molds are part of the kingdom fungi and are related to mushrooms and yeasts. They reproduce by growing from microscopic units called spores. From these spores, mold growth can occur on surfaces of consumer products when sufficient moisture is present for some period of time, and the surface is composed of or contains an available food source for mold growth—examples include mold growth on old bread or cheese long forgotten in the back of the refrigerator. Extending from the spore, mold grows by means of root-like structures called hyphae and grow in masses to give rise to more spores. This growth is called colonization. Although individual spores and hyphae are too small to see with the naked eye, with sufficient growth, they are visible as a familiar fuzzy or powdery colony. The spores of many mold species become airborne readily when physically disturbed, later settling onto surfaces; and if a spore happens to land on a surface with moisture and food, the cycle begins again. Spores can come from indoor sources, but the major source of indoor mold spores is outdoor air which is enriched with spores from soil and vegetation; spores from the outdoors are also transported indoors on and by objects, people, pets and pests. These are the mechanisms that result in the ubiquity of mold spores on normal surfaces.

In general, the mold spores present at normal background levels are not a cause of illness. But with sufficient exposure, mold spores can cause human illnesses by three specific mechanisms: allergy, infection, and toxicity. People with allergies to mold may experience allergic reactions, including hay fever symptoms and exacerbation of asthma symptoms with sufficient exposure to mold types to which they are sensitive. Mold can cause systemic infection in people with compromised immune systems (e.g., cancer patients receiving chemotherapy, organ transplant patients receiving immunosuppressive drugs), but fungal infections in healthy, immunocompetent individuals are mostly superficial (e.g., fungal infection of the nails, thrush) and are rarely caused by only a few of the many common mold types. Toxicity (or mycotoxicosis) in humans and other animals can occur when moldy food or feed that contains mycotoxins (chemicals produced by some molds under suitable environmental conditions) is ingested in sufficiently large amounts. Mycotoxicosis from dermal (skin) exposure or the inhalation (breathing) of mold fragments or spores has not been demonstrated in humans and does not appear to be plausible.3

In sum, exposure to mold spores on consumer products cannot be avoided. Mold will not grow when the consumer product is kept clean and dry. It is unlikely that a “few mold spores detected” could result in any adverse health effects for the user of a comforter.



  2. United States Consumer Product Safety Commission. Recall list. Available at
  3. Bush, R.K., Portnoy, J.M., et al.  The medical effects of mold exposure. Position paper of the American Academy of Allergy, Asthma and Immunology. J Allergy Clin Immunol 117(2): 326-333. 2006; Council for Agricultural Science and Technology (CAST).  Mycotoxins: Risks in Plant, Animal, and Human Systems. Report no. 139. Ames, IA. 2003; Institute of Medicine - Committee on Damp Indoor Spaces and Health.  Damp Indoor Spaces and Health. Washington, DC: The National Academies Press, National Academy of Science. 2004; World Health Organization.  WHO Guidelines for Indoor Air Quality: Dampness and Mould. WHO Regional Office for Europe, editor. Copenhagen. 2009.

About the Author

Clara Chan, MSc, DABT

Senior Toxicologist

Clara Chan, MSc, DABT, provides technical support and served as a consultant for projects in areas of toxicology, risk assessment, personal injury litigation, consumer product safety, and industrial hygiene.

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