Short-term microfiltration experiments were performed to measure the removal of two gram-negative bacteria (Brevundimonas diminuta and Serratia marcescens), two bacterial viruses (PRD1 and T4), and several spherical silica particles in a stirred cell under convection-dominated conditions before the onset of fouling. These (bio)colloids ranged from being spherical- to rod-shaped, with an aspect ratio in the range of 1-9. Experimental measurements of the removal of spherical silica and spherical PRID 1 bacteriophages were in good agreement with theoretical predictions. A comparison of experimental results for the removal of rod-shaped microorganisms to predictions from a previously developed hindered transport model for capsule-shaped particles indicates shear alignment of the rod-shaped particles within the membrane pore, with microbial passage biased toward an "end on" configuration. Results show that, under the conditions of our measurements, microorganism removal by membranes can be conservatively estimated using the rod diameter as the size parameter in hindered convection predictions.