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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
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  • Jitendra Patel,
  • Grishma S. Prabhukhot,
  • Hsin-Bai Yin,
  • Charles D. Eggleton,
  • Moon Kim
Jitendra Patel
US Department of Agriculture

Corresponding Author:[email protected]

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Grishma S. Prabhukhot
University of Maryland Baltimore Department of Mechanical Engineering
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Hsin-Bai Yin
Center for Food Safety and Applied Nutrition
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Charles D. Eggleton
University of Maryland Baltimore Department of Mechanical Engineering
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Moon Kim
US Department of Agriculture
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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/m 2. 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/m 2, 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/m 2, and PTFE and EPDM at 0.088 N/m 2. Our study emphasizes the importance of surface skewness, peaks, valleys, flatter areas, over surface’s roughness while selecting the material for food processing environments.