Fungal deterioration of a woollen textile dyed with cochineal

Microbiological destruction of woollen textiles may occur as a result of the influence of both bacteria and fungi and it is connected with their nutrition. However, in view of the conditions endured by the fabrics during transport, storage or museum exhibitions, fungi pose the greatest threat, due to their physiology. Fungal activity, by causing irreparable damage to woollen textiles, may lead to the irreversible loss of cultural properties. In this work, assessment of the mode of action of selected fungal species on cochineal-dyed woollen textiles was performed. Furthermore, determination of the impact of enriching a microbiological medium with additional nutrients upon the degree of biodeterioration of the dyed textiles was carried out. Experiments were conducted using the pure culture method. To analyse the type and extent of microbial deterioration of the cochineal-dyed woollen textile's tensile strength, elongation tests and spectrophotometric measurements of colour were applied. Additionally, selected samples were analysed by both transmitted light and scanning electron microscopy (SEM). The undertaken research showed that all the fungi tested cause structural and aesthetic damage, of varying degrees, to the woollen textile. Moreover, the presence of additional nutrients in the medium is a significant factor, which determines the susceptibility of a particular textile to microbial deterioration.