A microfilter should retain micron-sized material yet provide minimal resistance to liquid flow. A slotted pore surface microfilter was oscillated while filtering yeast cells under constant rate. At shear rates over 7760 s(-1), a pore blocking model fitted the data. The operating pressure was very low (< 1000 Pa), but particle retention was limited by the 4 micron pore slot width. A sintered glass micro-bead coating improved yeast rejection: 95% at 1.7 microns at a shear rate of 5000 s(-1), with a 1.2 kPa transmembrane pressure. Two models were validated to assist with the design of future micro-bead coatings constructed from spherical particles.