After landing on a host material, a spore must obtain sufficient moisture to germinate and find enough food. Without moisture, the spores will lie dormant until favorable conditions occur. For this reason, it is important to control the environmental conditions where museum collections are stored or exhibited. These conditions are maximum levels and only reduce the potential for microorganism growth. They do not eliminate he threat.
Some microorganisms can grow in significantly lower temperatures and at lower RH levels.
Certain materials need to be stored with lower RH levels to prevent growths. Some species of microorganisms cause health risks in the form of chronic lung irritation. Susceptible Materials Microorganisms need organic materials to supply nutrients and, therefore, museum objects composed of organic materials are potentially at risk. Cellulose-based materials, such as cotton, linen, paper and wood, and proteinaceous materials such as leather and hair loth are particularly susceptible to direct attack by microorganisms. Inhospitable materials, such as plastics, are not immune from fungal growths but how they support these growths is not fully understood by biologists.