Mechanistic understanding of non-spherical bacterial attachment and deposition on plant surface structures

- Simulation validated for translational and rotational motion.
- Trichomes decrease and stomata increase overall attachment.
- Attachment to trichomes predominately normal to flow.
- Attachment to stomata and grooves upstream and downstream of flow.

Bacterial attachment to the surface and passive internalization to fresh produce is the first step in contamination of food. Understanding the mechanism of attachment and internalization could lead to the prevention of future outbreaks on fresh fruits and vegetables. The goal of this model was to validate and use a Lagrangian particle tracking simulation of a spherocylinder shaped bacteria, Escherichia coli, to determine the effect plant surface structures have on attachment. Rotation of the cells was validated versus theoretical and experimental data. Also, simulation results of attachment were validated versus experimentally measured cells to microfabricated plant structures: stomata, trichomes and grooves. The simulation results showed how trichomes decreased attachment by lowering shear stress within the microarray while stomata and grooves enhanced attachment by creating small regions of increased shear stress triggering shear enhanced adhesion. Microstructures affecting the local fluid shear stress, and not residence time, increased attachment.