Quantification of lipids and protein in thin biofilms by fluorescence staining.
The efficiency of removing unwanted biofilm from surfaces in industrial water systems was examined by fluorescence microscopy and image analysis. A quantitative assay for in situ determination of biofilm components was developed and tested on thin biofilms grown in reactors as well as real biofilms sampled from a fish processing factory. Different fluorescent dyes for in situ detection of protein, lipid and total organic matter were tested. It was possible to determine the approximate amounts, concentrations and coverage of the different components by correlating the fluorescent intensity of the biofilm components to standard solutions immobilised as a biofilm. The quantification methods were evaluated as a strategy for determining the efficiency of different disinfection/cleaning procedures, showing that quantification of these biofilm components was fast and reliable for optimisation of cleaning in place procedures. However, the approach also showed that bacterial cells, as investigated by culture-independent procedures, were killed but not removed by most disinfection procedures tested, potentially leading to surfaces which are easily recolonised.
Larsen
Poul
P
Department of Biotechnology, Chemistry, and Environmental Engineering, Aalborg University, Aalborg, Denmark.
Olesen
Bo Højris
BH
Nielsen
Per Halkjaer
PH
Nielsen
Jeppe Lund
JL
D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry*; D018441:Biofilms / Q000254:growth & development*; D005399:Fishes; D005456:Fluorescent Dyes; D019649:Food Industry; D007091:Image Processing, Computer-Assisted; D008055:Lipids / Q000737:chemistry*; D008856:Microscopy, Fluorescence; D009930:Organic Chemicals; D010078:Oxazines; D013194:Staining and Labeling; D013193:Stainless Steel
D001426:Bacterial Proteins; D005456:Fluorescent Dyes; D008055:Lipids; C433144:NanoOrange; D009930:Organic Chemicals; D010078:Oxazines; D013193:Stainless Steel; C044808:nile red