Cleanability study of complex geometries: Interaction between B. cereus spores and the different flow eddies scales

Wall shear stress measurements and the distribution size of turbulent structures at the confined zone near the wall were used in order to investigate the cleanability of a part of a dairy processing line consisting in a manometer and a two-way valve. Geometry of equipment was discerned as an important factor governing the flow behavior and thereafter the initial contamination and the cleanability of the installation. Interactions between suspended spores and coherent turbulent structures of different sizes were used to explain the eventual re-adhesion of spores in confined zones of the loop. These interactions also helped to explain the role of the bursting phenomenon in the increase of the wall shear stress which induces spores detachment.