Window seals as a source of yeast contamination

The study aimed to assess the taxonomic diversity of fungi isolated from window seals and analyse their ecophysiological properties, understood as a description of morphological and biochemical features, creating a biofilm, growth rate on model mediums with different water activity. The study material was swabs collected from the lower window seals in 28 bedrooms and five kitchens in temperate climate zone, taken during heating season. A total of 26 fungal isolates were obtained: 20 isolates from eight species on the bedroom and six out of four species on the kitchen. The chance of fungus occurrence on kitchen seals is almost twice as high as in the bedroom, while the expected species diversity is nearly six times higher in the bedroom than on kitchen windows. The low-carbohydrate environment with variable physical parameters promoted nonfermenting vitamin prototrophs with high adhesion abilities. The only species that can use nutrients derived from plasticizers of window seals were Aureobasidium pullulans. The presence of potentially pathogenic species on window seals is disturbing. All obtained fungi showed the ability to create a biofilm and produce dyes. Many isolates with dye on seals are related to the rooms' biota diversity. Their presence on windows should be constantly monitored.