Assessment of the environmental conditions in a museum storehouse by use of a fungal index

Fungal contamination (foxing) was detected on a painting stored in an art museum. The internal environments were assessed using a fungal index. The index is a biological climate-parameter, which represents the environmental capacity to allow fungal growth. To determine the index, fungal detectors encapsulating the spores of sensor fungi were placed at the site being examined. The growth response, germination of the spores and hyphal extension, of xerophilic sensor fungi was observed in the storehouse. The values of fungal index predicted propagation of fungi, although dehumidifiers were already in use. Next year, the number of dehumidifiers installed in the storehouse was increased from 3 to 8. After the number of dehumidifiers was increased, the indices were below the detectable limit in the storehouse indicating no fungal contamination will occur. The sensor fungi used in those assessments were five xerophilic and two non-xerophilic strains. In the assessment before countermeasures were taken, Aspergillus penicillioides showed the highest growth response among the sensor fungi in the fungal detector exposed in the room where the contaminated painting was stored. Eurotium herbariorum showed the highest growth response in other rooms. These two strains were selected as the sensor fungi for assessments of museum environments.