The objective of this study was to investigate the roles of mechanical and chemical actions on the detachment kinetics during CIP of biofilms of Pseudomonas fluorescens at a pilot-plant scale. Biofilms were grown 48 h at 20 degrees C in diluted milk. Shear stress conditions ranged from 0 (static) to 20 Pa and NaOH concentrations from 0.1 to 0.5% w/w. A simple two-phase model was applied to model the removal kinetics and compare detachment parameters. A quick removal of the biofilm during the first phase (4-5 log decrease in three minutes) was followed by a second phase of slow removal of the cells and small aggregates still present at the surface (0-2 log decrease). Hydrodynamics was responsible for removal of both biofilm and single cells while chemicals mainly disrupted biofilm clusters during the first phase. No complete biofilm removal was observed, suggesting a significant role of the interaction forces between bacteria and substrata in the CIP efficiency. (C) 2017 Elsevier Ltd. All rights reserved.