Abstract: The invention is directed to a method for detecting the presence of biofilm-forming microorganisms in a paper or board making process for determining the need of an anti-biofilm agent in the process. The method comprises the steps: (a) subjecting a sampler device in the process line for a period of time to enable said microorganisms to form a biofilm in situ in said process on the surface of the sampler, (b) optionally treating said formed biofilm in a solution of a test anti-biofilm agent for a period of time, then (c) contacting said biofilm with a liquid growth medium in a recession of a culturing device for a period of time, and (d) removing the growth solution from the recession of said device and detecting qualitatively and/or quantitatively the presence or absence of a biofilm adhered on the walls of the recession. An assembly kit is also provided.

Abstract: The invention relates to a method of inhibiting the biofilm formation by thermophilic adhering microbes of paper and board machines on the surfaces of paper or board machines, and/or removing such biofilms from the said surfaces by adding to the circulation waters of the paper or board machines at least one pure substance isolated from a plant or at least one plant extract or a mixture thereof in such a concentration which is effective against thermophilic adhering microbes. The invention further relates to a method of determining the need of the addition of an anti-biofilm agent in paper and board manufacturing processes, and an assembly kit suitable for the same.