Influence of the design of fresh-cut food washing tanks on the growth kinetics of Pseudomonas fluorescens biofilms

Summary Mitigation of cross-contamination of fresh-cut food products at the washing step was studied by investigating how the vat design would affect the biofilm contamination surfaces. Hygienic design features such as no horizontal surfaces and only open angles exceeding 100° were proposed. The flow organisation (velocity streamlines, wall shear stresses, dynamics of the flow) was identified by means of computational fluid dynamic (CFD) calculation. Pseudomonas fluorescens PF1 biofilm growth kinetics were then mapped. The change in some geometrical features induced a better flow organization reducing “dead zones”. This significantly changed the biofilm growth kinetics, delaying the detection of biofilms from 20 h to 24 h. Critical areas such as welds, corners and interfaces appeared far less prone to strong bacterial development. This would mean milder or less chemicals required at the washing step and faster and easier cleaning.