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Microbiological methods for testing disinfectant efficiency on Pseudomonas biofilm.
1VTT Biotechnology and Food Research, PO Box 1500, Tietotie 2, FIN-02044 VTT, Espoo, Finland
Colloids and Surfaces. B, Biointerfaces
|November 21, 2000
Summary
Peroxide-based and chlorine-based disinfectants were most effective against Pseudomonas biofilms on stainless steel. Other disinfectants showed effectiveness in bacterial suspension but not on the biofilm surface.
Area of Science:
- Microbiology
- Food Science
- Surface Science
Background:
- Bacterial biofilms on stainless steel pose challenges in the food industry.
- Pseudomonas aeruginosa and Pseudomonas fragi are common Gram-negative bacteria forming biofilms.
Purpose of the Study:
- To evaluate the efficacy of different commercial disinfectants against Pseudomonas biofilms on stainless steel.
- To compare disinfectant effectiveness on bacterial cells in suspension versus within biofilms.
Main Methods:
- Biofilms of Pseudomonas spp. were grown on stainless steel surfaces.
- Disinfectant efficacy was assessed using suspension tests (permeabilisation assay with NPN) and biofilm analyses (cultivation, impedimetry, epifluorescence microscopy with acridine orange and CTC-DAPI staining).
Main Results:
- Tenside-based and peroxide-based disinfectants effectively permeabilised bacterial cells in suspension.
- Peroxide-based and chlorine-based disinfectants demonstrated the highest efficacy against bacteria within the biofilms.
- Disinfectant performance varied significantly between suspension and biofilm states.
Conclusions:
- Peroxide and chlorine-based disinfectants are recommended for controlling Pseudomonas biofilms on stainless steel surfaces in food industry settings.
- Assessing disinfectant efficacy solely in suspension may not accurately predict performance against established biofilms.