Classification of molds and definition of mold contamination

The term “molds” is defined and relevant sources of molds are given. The conditions and growth of mold fungi are explained. The determination of mould spores and colony-forming units (CFU) in the air is briefly explained and it is made clear that the total spore count is relevant for assessing the sensitizing and allergenic effect of moulds. Outdoor air-associated moulds such as Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum and Penicillium chrysogenum (mx1 mould mixture) are of particular importance due to their high degree of sensitization. Their concentration in the air is determined by the vegetation and is therefore dependent on the season. In people who were tested for mx1, sensitization to Alternaria alternata (m6) was predominantly observed for the individual allergens. For many indoor-associated moulds, no (valid) commercially available test extracts for the detection of sensitization, so-called allergy tests, are available. Allergy test results of mold mixtures, such as mx1, cannot be used to determine an indoor mold allergy, nor can the results of mold measurements in the rooms used by the respective persons be used for a risk assessment in the event of an existing mold infestation in the interior. The classification of mold fungi is explained.