Definition of Water Activity Water activity (aw) refers to “free” water available for microbial growth. For microbial growth to occur, moisture must be freely available. The water activity of a material determines which types of mold would grow on that material. Technically, the water activity is defined as the ratio of the vapour pressure exerted […]
The Phases of Fungal Growth in Indoor Environment
Fungal growth in both modern and historic buildings is attributed to environmental conditions such as water, humidity, temperature and lack of ventilation. Often, people will ask the laboratory if it is possible to tell how old the mold is and/or whether the mold was actively growing and what the source of the mold was. The […]
Wallemia Mold
Wallemia spp. The genus Wallemia is xerophilic. Three species of Wallemia have been identified. These are W. ichthyophaga, W. sebi, and W. muriae. Wallemia sebi is the most well known species. It has been isolated from air, soil, dried food (causing spoilage) and salt. Since the species within the genus Wallemia have been recognized only […]