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WORLD PULPPAPER 65 Patented DNA-based monitoring strategies are available to provide more accurate information regarding microbial growth and biofilm an appropriate chemical for their elimination. CUSTOMER EXAMPLE A coated freesheet mill was experiencing product quality issues due to an outbreak of sheet defects. Onsite biomonitoring using traditional plating and ATP tools did not indicate a microbiological problem. Analysis of sheet defects with MAP showed that the root cause of the problem were problematic bacterial species including adaptive and filamentous biofilm-formers Figure 3-1. Following a process survey the location of these bacteria in the process was identified to determine the most responsive addition point for the biocide Figure 3-2. Subsequent MAP testing confirmed eradication of problematic bacteria from the process Figure 3-3. CONCLUSION Conventional plating techniques and oxidant residuals may indicate adequate biocide dosing and control of microbial growth while deposition defects and breaks remain prevalent. Patented DNA-based monitoring strategies are available to provide more accurate information regarding microbial growth and biofilm formation in industrial water systems. These strategies allow for rapid analysis of the contribution of microorganisms to deposit formation and can be used to rapidly determine whether or not deposits containing microorganisms are contributing to defects. Quantitative PCR techniques allow for rapid analysis of sheet defects to determine the contribution of microorganisms to quality issues. This new approach has been demonstrated to allow for a more proactive diagnosis of problems leading to improved machine efficiency and product quality Figure 4. precision can be applied to the design and deployment of microbial control programs. CONNECTION BETWEEN MACHINE DEPOSITS AND SHEET DEFECTS The root cause of sheet defects is notoriously difficult to determine. High temperatures in the dryer section desiccate all microbial contaminants making them impossible to analyse using traditional plate counts or ATP techniques. The burden of identifying whether the defect is microbial or chemical in nature then falls on mill personnels experience FTIR or ninhydrin spray. The experience of mill personnel can be subjective and FTIR and ninhydrin spray detect chemical groups that are not unique to microorganisms. All of these approaches can result in inaccurate information that may lead to an improperly treated process. DNA is a robust molecule that can withstand extreme conditions of the dryer section. MAP makes it possible to detect bacterial DNA in sheet defects and identify problematic species present therein thus making it possible to determine with certainty whether the root cause of the problem is chemical or bacterial in nature Figure 1. Based on the type and quantity of microorganisms present their origin can be traced back to a specific source in the process. IDENTIFICATION OF HOT-ZONES OF PROBLEMATIC BACTERIA IN THE PROCESS Once the root cause of a sheet defect has been recognised as microbiological and the implicit bacterial species identified it is important to eliminate the source of these bacteria from the process. Using MAP to perform a thorough process survey allows for the type and quantity of target bacteria to be determined to track their origin back to a specific location or raw material source in the process or locations that serve as proliferation zones for these bacteria. TARGETING THE MOST EFFECTIVE CHEMICAL TO THE MOST RESPONSIVE ADDITION POINT When the identities and location of problematic organisms are known it is possible to accurately target the right chemicals to correct the problem. Knowing which organisms are present makes it easier to select Figure 4. MAP Technology allows for proactive diagnosis of microbial problems leading to targeted treatment strategies that and quality