Mildew Staining of Jute Materials

Abstract

Mildew stains in jute materials are usually produced by certain "superficial" species of fungi belonging to the genera Penicillium and Aspergillus, which cause little or no loss in strength. Metabolic acids, often produced simultaneously, may deepen the stain, and one fungus produced enough oxalic acid to cause acid staining. Apart from metabolic pigments, stains may be caused by colorless products combining with the non-cellulosic fractions of jute. This and the fact that superficial fungi grow more easily on jute than cotton render the former more susceptible to mildew staining. Other species which failed to produce stain in inoculation experiments but gave strongly staining filtrates may be implicated in the staining of jute. For some unknown reason, sacking proved less susceptible to staining than other fabric materials.