Adhesion behavior and removability of Escherichia coli on stainless steel surface

Adhesion behavior of Escherichia coli from its suspension onto stainless steel (type 304) surface was studied, focusing on the effects of initial cell concentration of suspension, suspending medium, and roughness of stainless steel surface. The results demonstrated that the adhesion of E. coli was significantly enhanced by the cell concentration of contaminants. The adhesion was observed even in short contact periods of time, but it increased and reached a plateau within 3–4 h. The plateau value of surface cell density was roughly proportional to the cell concentration of the suspension. Rinsing experiments indicated that a relatively high percentage of cells were found to be irreversibly attached on the surface when peptone saline was used as a suspending medium. The adherent cells were however shown to be quite vulnerable to removal with water as a rinsing medium. Moreover surface roughness was found to affect the removability of adherent cells.