Two-phase kinetics of biofilm removal during CIP. Respective roles of mechanical and chemical effects on the detachment of single cells vs cell clusters from a Pseudomonas fluorescens biofilm

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.