DIN ISO 16000-17:2010-06

Mould is a common name for filamentous fungi from different taxonomic groups (Zygomycetes, Ascomycetes [Ascomycota], Deuteromycetes). They form a mycelium (hyphae) and spores - namely conidiospores (conidia), sporangiospores or ascospores - by which they become visible macroscopically. Most spores are in the size range 2 µm to 10 µm; some up to 30 µm and only a very few up to 100 µm. Spores of some mould genera are very small and become airborne very easily (for instance Aspergillus, Penicillium) while others are bigger and/or embedded in a slime matrix (Stachybotrys, Fusarium) and less mobile. Mould spores are widely distributed in the outdoor environment and, therefore, also occur in varying concentrations indoors. Growth of moulds in indoor environments, however, should be considered a hygienic problem because epidemiological studies have revealed that dampness and/or mould growth in homes and health impairment of occupants are closely related. Standardized methods for sampling, detection and enumeration of moulds, as well as for sampling strategies are important for comparative assessment and for remedial measures of mould problems indoors. This part of ISO 16000 specifies requirements for the detection and enumeration of moulds by cultivation after sampling by impaction according to ISO 16000-18 or by filtration according to ISO 16000-16. The method is also suitable for cultivation of moulds from material suspensions or contact plates and from direct plating. Principle: Agar plates (DG18 agar and malt-extract agar or potato dextrose agar) obtained from sampling by impaction are incubated directly at (25 ± 3) °C. Filters obtained from sampling by filtration are re-suspended in saline solution (0,9 % mass fraction NaCl) with 0,01 % polysorbate 80. Decimal dilutions of the suspension are prepared and aliquots spread on DG18 agar as well as on malt-extract agar or potato dextrose agar (indirect method). Agar plates are incubated at (25 ± 3) °C. For special purposes plates can be incubated at (36 ± 2) °C (for instance thermotolerant Aspergillus spp.) or (45 ± 2) °C (Aspergillus fumigatus). After incubation, mould colonies are identified and counted. The International Standard has been prepared by ISO/TC 146/SC 6 "Indoor air", by Working Group 10 "Fungi", the secretariats of which are held by DIN and which are under German chairmanship. The responsible German Committee is NA 134-03-07-04-01 AK Gemeinschaftsausschuss Bioaerosole und biologische Agenzien (Joint Committee "Bioaerosols and biological agents").