All process water involved in ceramic production, both tap and well waters, usually contains bacteria. And the same applies to inorganic raw materials used in the grinding process to produce the semi-finished products that will later be applied along the glazing line: frits, clays, feldspar, nepheline, etc.  Because of the huge amount of water use, glazes and engobes grinding departments can sometimes be under the attack of significant bacterial proliferations. Microorganisms' activity (especially that of bacteria) is able to decrease or even nullify the action of chemicals that should provide suspensions with the right features to develop a proper application, also ensuring outstanding technical and aestethic results. In this perspective, what are the main consequences of bacterial degradations?