Electronic nose for the early detection of moulds in libraries and archives

The development of sensor technology has stimulated interest in the use of characteristic volatile and odorous compounds produced by fungi as early indicators of deterioration in materials. Sensor arrays to measure traces of volatile chemicals could detect early fungal growth in libraries and archives. In this study we tested an electronic nose to detect fungi actively growing on paper samples. The main aim was to verify whether or not a device, currently used to detect fungal activity in stored grain, might be suitable for detecting mould activity on paper. The findings indicate that it is possible to discriminate "in vitro" between paper samples affected by moulds and those unaffected, both at 100% RH (relative humidity), and at 75% RH, simply by measuring their odour fingerprint with an electronic nose. The sensors used in this study discriminated for each paper type three different species of actively growing fungi. Cluster analysis (CA) showed it was possible to differentiate between specific species. Different. paper types influenced the emission of odorous signals by moulds. When considering data from all the paper types, principal component analysis (PCA) indicated that only samples analysed at 100% RH could be separated. This study suggests that, before electronic-nose technology can be applied to the early detection of mould growth in libraries, archives, museums or in display cases, more information will be required on the influence of substrata and of other environmental parameters in the production of volatile chemicals by fungi.