The effects of book disinfection to the airborne microbiological community in a library environment

The management of fungal contaminants inside libraries and archives has become a big challenge for librarians, restorers and scientists. Several disinfection treatments have been developed in recent years, using both chemical and physical approaches on book collections and indoor environments. However, there is a lack of knowledge about the temporal efficiency of these cleanings, especially in relation with the preservation environments. The aim of this study was to determine the long-term effect of a chemical disinfection that interested a previous-contaminated book collection inside a University library. The monitoring after 6 months and 1 year from the cleaning confirmed any fungal growth on the disinfected books and the reduction of 90% of the airborne fungal load, highlighting anyway the presence of high fungal diversity. Sixty-eight different airborne fungal entities were isolated, in particular Aspergillus vitricola, Bulleromyces albus, Cladosporium cladosporioides, Cladosporium pseudocladosporioides, Cladosporium sphaerospermum, Penicillium brevicompactum, Rodothorula mugillaginosa and Sporodiobolus pararoseus. Several fungal species were sampled from the disinfected books, in particular Aspergillus penicillioides and Penicillium chrysogenum. The presence of these fungi both as airborne and as settled particles highlights the importance to maintain clean the preservation environments in order to prevent further microbial contaminations.