3. Analysis techniques

In the event of large-scale contamination of collections, it is necessary to take quantitative and qualitative measurements of the micro-organisms present in the air and on surfaces, in order to determine the microbiological quality of the store(s). The detection techniques used are based on culturing the particles collected. Deposited on a suitable nutrient medium, the micro-organisms give rise to colonies visible to the naked eye. The culture media used depend on the micro-organisms in question. For molds, we generally use a non-specific medium such as malt-agar (MA), sabouraud or malt-yeast extract-agar (MEA), and a medium for xerophilic strains such as dichloran-glycerol (DG18). For documents with suspect stains, samples need to be taken and cultured to assess the nature of the stains, and to determine the viability of contaminating strains if they are micro-organisms. These cultivation...