Microbial contamination of libraries and archives: risk assessment and contamination control

Freezing of the paper material is a way to control the growth of microorganisms and the possibility of “acute” biodeterioration and illness, after accidental events, e.g. flooding. But as the paper-born microorganisms can survive after lyophilisation, they must be controlled also after the drying process. The decision-making about the adoption of prevention and protection measures for the exposed operators’ safety, among which the possibility to control the biodeteriogenic and toxigenic microflora growth by the application of Thymus vulgaris oil, was supported not only by the experimental results but also through a dedicated risk assessment procedure.