1. Institute of Chemical Technology Prague
Department of Food Preservation and Meat Technology
Effect of physicochemical surface characteristics on bacterial attachment
Petra Sedláčková

2. Bacterial adhesion x Biofilm formation
effect of surface characteristic
microorganism used for attachment – widely described in nature, isolated in food processing environments

3. Microorganisms Pseudomonas fluorescens (DBM 3113 BHA)
gram-negative, aerobic bacterium, cat.+, ox.+
scanning electron micrographs of Pseudomonas biofilm formation

4. Escherichia coli (DBM 3125 BHA)
gram-negative, cat.+, ox.-
scanning electron micrograph of E. coli biofilm formation

5. Asaia bogorensis gram-negative, aerobic bacterium, cat.+, ox.-
scanning electron micrographs of A. bogorensis biofilm formation

6. Tested surfaces stainless steel – AIS 304
40 x 40 mm, tested area 13 x 13 mm
the slides were washed in sanitizers solution, rinsed by distilled water and autoclaved at 121 °C for 20 min

7. glass – for the microbial purpose
76 x 26 mm, tested area 13 x 13 mm
the slides were washed for 30 min in sanitizers solution, rinsed by distilled water , were placed on aluminium foil, covered and autoclaved at 121 °C for 20 min

8. evaluation incubation (3,6,12,24 hr)
rinsing by sterile nutrient broth + addition nutrient broth
incubation (24 hr)
100 μl
evaluation

9. bacteria were scraped from test surfaces with a cotton-wool swab
transferred into test tube containing 10 ml physiological solution
stirred for 1 min to release the cells into the solution
agar
agar
Cultivation on agar:
P. fluorescens: 25 °C, 24 hr, A. bogorensis 25 °C, 48 hr, E. coli 37 °C, 24 hr

10. Attachment of P. fluorescens, A. bogorensis, E
Attachment of P. fluorescens, A. bogorensis, E. coli on stainless steel and glass
Detection limit 2,9 * CFU * cm -2

11. a) 3, 6 ,12 ,24 attachment of Asaia bogorensis
b) 3, 6 ,12 ,24 attachment of Pseudomonas fluorescens
detection limit 2,9 * CFU * cm -2
c) 3, 6 ,12 ,24 attachment of Escherichia coli

12. attachment of all tested microorganisms on stainless steel x glass
Detection limit 2,9 * CFU * cm -2

13. Conclusion
P. fluorescens at 3 hr incubation had higher attachment values compared to other tested microorganisms.
Cell numbers for 24 hr biofilms are significantly different between P. fluorescens and Escherichia coli.
No significant effect of initial attachment on biofilm growth (for each microorganism) between stainless steel and glass was found.