Water system closure has a profound influence on odor problems. Chemicals can cycle up in the process water, where years ago they were flushed out and did not cause problems. On the plus side costly additives and fines are retained, energy is conserved and water treatment costs are reduced. On the minus side, we find increased problems with odors. Nutrients that serve as food concentrate when the water system is closed. Anaerobic bacteria that were unable to grow in an open water system thrive. This is usually coupled with increased water system temperatures that reduces the dissolved oxygen content of the fluids and further aids in conditions amenable to anaerobes. Typically, anaerobes produce foul smelling hydrogen sulfide and VFA.
Certain materials strongly absorb off odors. Fatty foods such as butter or chocolates tend to pick up certain off odors and packaging containing this board may require special treatment to avoid damaging the delicate flavors. In Europe, containerboard for certain high-end chocolates utilizes special technology to absorb and neutralize compounds that interfere with the flavors.
Silk is another material that quickly adsorbs foul odors. Since silk is often considered a luxury product and products made from silk can be very expensive, packaging expensive lingerie or designer ties in boxboard that reeks of volatile fatty acids (VFA) is not desirable. The figure above lists various causes of odor complaints in paper and board that have been described in the industry and/or encountered by the author.
Consults on anaerobic bacteria odor, industrial microbiology, and biocide
From: Linda R. Robertson "Undesirable odors in finished paper and paperboard products" Tappi Papermaker Proceedings Atlanta, TAPPI Press, Atlanta April (2006).
Not all malodors are caused by microbes.
Industrial Microbiology Consulting
Odor & slime problems lead to off spec products caused by bacteria & fungi. Environmental microbiology ]