A methodology for detecting the level of fungal contamination in the French Film Archives vaults

The Archives françaises du film ([AFF] French Film Archives) of the Centre national du cinéma et de l’image animée (National Center for Cinema and the Moving image [CNC]) is regularly facing problems of molds growth on cinematographic films enclosed in plastic and metal containers. This study is conducted through comprehensive microbiological testing on films, shelves and air quality for the AFF storage sites (Saint-Cyr and Bois d’Arcy), in order to understand the origin of fungal development and subsequently to suggest a suitable solution to eradicate ongoing mold growth and to combat further contamination. The air analysis shows that the amount of airborne mold on both sites is small with concentrations 3 times less than level 1 (<170 CFU m−3), which is considered as a weak threshold for indoor environment concentrations. An increase of outdoor air concentration of mold has no effect on indoor concentrations. On the other hand, on surfaces, fungal concentration can reach 4 times the limiting value (50 CFU dm−2). No direct relationship was observed between the contamination in the air and shelves. Molds that have grown on film rolls include mainly and at a high frequency two xerophilic species with a strong gelatinolytic capacity: 62.5% were identified as Penicillium corylophilum (Aw 0.80) and 18.75% as Aspergillus versicolor (Aw 0.78). Because they are scarce in the air and on surfaces, it indicates that the films were not contaminated inside the storage areas. However, unfavorable climatic conditions in the storage vaults have triggered mold development inside the plastic or metal containers.