Impact of surface topography and shear stress on single and dual species biofilm formation by Escherichia coli O157:H7 and Listeria monocytogenes in presence of promotor bacteria

Authors: PRABHUKHOT, GRISHMA - University Of Maryland; YIN, HSIN-BAI - Food And Drug Administration(FDA); EGGELTON, CHARLES - University Of Maryland; Kim, Moon; Patel, Jitu

Submitted to: BIOFOULING
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2024
Publication Date: 5/28/2024
Citation: Prabhukhot, G., Yin, H., Eggelton, C., Kim, M.S., Patel, J.R. 2024. Impact of surface topography and shear stress on single and dual species biofilm formation by Escherichia coli O157:H7 and Listeria monocytogenes in presence of promotor bacteria. BIOFOULING. 201: e116240. https://doi.org/10.1016/j.lwt.2024.116240.
DOI: https://doi.org/10.1016/j.lwt.2024.116240

Interpretive Summary: Disease-causing bacteria (pathogens) can attach to equipment surfaces at the food processing facility. Once attached, these pathogens may form biofilm on surface which is difficult to remove with commonly employed sanitizers, and subsequently contaminate food during processing. We evaluated biofilm formation of E. coli O157:H7 and L. monocytogenes in the presence of promotor bacteria R. insidiosa on different equipment surfaces at various hydrodynamic shear stresses. Single species E. coli O157:H7 biofilms were significantly higher on polycarbonate compared to rubber surface at 0.043 and 0.088 shear stresses. The effect of surface material on single species E. coli O157:H7 biofilm formation was not evident at lower shear stress of 0.013 N/m2. Higher L. monocytogenes biofilm formation was observed in presence of R. insidiosa on PTFE at 0.043 and 0.088 N/m2. Scanning electron microscopy revealed that surface skewness (peaks and valleys) of material significantly influenced biofilm formation of bacterial pathogens. The findings are helpful to food processors in selecting equipment with surfaces which provide minimal bacterial attachment.

Technical Abstract: Biofilm formation ability of E. coli O157:H7 and L. monocytogenes in the presence of promotor bacteria R. insidiosa was evaluated on stainless steel, polycarbonate, PTFE, and EPDM coupon surfaces under hydrodynamic shear stresses of 0.013, 0.043 and 0.088 N/m2. Surface roughness and topography of coupons were recorded; surface roughness of stainless steel, EPDM, polycarbonate, and PTFE was 0.71, 1.11, 2.36 and 3.17 µm; respectively. Coupons used in a Centers for Disease Control and Prevention biofilm reactor (CBR) were inoculated with 1 ml of individual bacterial inoculum (~9 log CFU/ml). Single species E. coli O157:H7 biofilms were significantly higher on polycarbonate compared to EPDM at 0.043 and 0.088 shear stresses. At lower shear stress of 0.013 N/m2, the single species E. coli O157:H7 population were similar on all materials indicating that single species E. coli O157:H7 biofilm formation is non-surface-specific at this shear stress. Higher L. monocytogenes biofilm formation was observed in presence of R. insidiosa on PTFE at 0.043 N/m2, and PTFE and EPDM at 0.088 N/m2. Our study emphasizes the importance of surface skewness, peaks, valleys, flatter areas, over surface’s roughness while selecting the material for food processing environments.