
Wallemia sebi is one of the so called xerophilic moulds, meaning that it can grow under relatively dry conditions (i.e., low water activity). Wallemia sebi has a world-wide distribution. It is common in indoor environments and has been isolated from jams, dates, bread, cakes, salted beans and fish, bacon, fruits, soil, hay, and textiles. It is also common in agricultural environments where it is suspected to be one of the causes of farmer's lung disease and other human allergies.
Wallemia sebi also produces a mycotoxin called walleminol A. Not much is known about the health effects of this toxin to humans in an indoor environment.