Conventional standard challenge test methods for detecting and measuring microbial growth on textile materials and for assessing the efficacy of biocides in textile applications require extended incubation periods. Various rapid speed methods for assessing biodeterioation of textile substrates have been proposed (bioluminscent assays, fluorescein diacetate hydrolysis etc.). Such methods require the deliberate infection of the material (under laboratory conditions) combined with the relevant method of damage assessment, following reduced test duration. Such rapid methods may facilitate in-house biocide application control.