Bacterial degradation of ceramic semi-finished products can occur for various reasons, but the most important is the simultaneous presence of water and organic material (which serves as food for bacteria).

In general, bacterial activity begins as soon as water is added to the mixing tanks. This is why bacterial activity is rarely observed in powders and water-free products. When bacteria activate their metabolism, they initiate their contaminating activity.

The main components of suspensions prone to contamination, and thus the organic parts primarily attacked by bacteria, include:

1. Organic raw materials

2. Organic matter derived from raw materials

3. Chemicals of natural or synthetic origin (organic or inorganic in nature, serving various functions depending on their purpose)

Bacteria are almost always present in materials of natural origin. They can be found in the milling water, dispersed in the air, and often within containers and/or on tools used in the preparation of semi-finished products.

Bacterial degradation, by partially or completely altering the rheological properties of the suspension, essentially compromises its proper use during the application phase.