ABSTRACT
This chapter identifies the most reliable method for the recovery of water-borne indicator organisms from flood-prone urban surfaces. It aims to define a reliable sampling method for the microbiological assessment of surfaces after floods. Four different sampling methods were compared: swabbing, direct agar contact, stamping and adhesive tape-lifting. The efficiency of swabbing and contact plating on surfaces was studied under simulated flood conditions. Swabbing was tested on different surfaces of glass, pavement, concrete and asphalt. The maximum volume of wetting solution absorbed by the swab heads was measured by dipping dry swabs in demineralised water and weighing the difference. The recovery ratios of swabbing and direct agar contact, widely used for smooth and non-porous surfaces, are compared with the indirect sampling methods of stamping and adhesive tape. The reason for the low efficiency of this indirect contact method was mainly the poor contact of the rubber on the sampled surfaces.
