The influence of microbial contamination on the quality of printing paper

Uncontrolled growth of bacteria and fungi in the papermaking process adversely affects machine runnability. How this growth influences factors in the finished sheet and sheet print properties is often overlooked, even though it can have a profound effect on printing characteristics. Many of the materials used in making paper coatings are excellent microbial nutrients. In addition to being nutrients, these compounds are critical to performance. For example, coatings made of poorly preserved clays can form a surface that has fine scratches caused by microagglomeration of the clay particles. This may be caused by microbial degradation of the dispersants in the clays. This paper will explore these issues and discuss steps that can be taken to minimize these problems.