The greatest danger in the storage and handling of paper and paper products is the formation of mold due to a number of fungi and the inability to use the paper. Mold attack is inevitable for all organic materials that are particularly exposed to unfavorable weather conditions or stored under unfavorable conditions. Because the fungus spores, which cause mold growth, are always present in the air and on various objects. On the surface of the paper stored in damp conditions, mold becomes manifested by staining in the form of raised spots. Mold is the apparent development of various fungi.

Mushroom varieties on paper secrete enzymes and cause breakdown. These parts are absorbed by the fungi in a solution manner. In this way, the paper is damaged both physically and biochemically.

Fungus analysis of paper and paper products is carried out in authorized laboratories within the scope of microbiology tests. The standards adopted in these studies are as follows:

• ASTM D 2020-92 Standard test methods for mold (fungus) resistance of paper and paperboard

These test methods are particularly used to determine the mold (fungus) resistance of paper and paperboard which are resistant to fungi. There are two test methods:

• Method A: direct inoculation, pure culture, non-anhydrous sample
• Method B: burying

The first method applies to paper products that are expected to be used or stored in a humid, warm atmosphere. However, these products do not come into contact with moist soils. This method is most preferred.

The burying method is recommended for all types of paper, whether or not it has been subjected to a fungus-resistant treatment, which may be in contact with moist soils for a long period of time.

Other standards, such as ASTM D 585, ASTM D 828, ASTM D 1193, and ASTM D 1968, are also applicable when applying these methods.