Determination of Faecal Coliforms in Sea Water by the Multiple Test Tube Method

The method described is suitable for the determination of faecal coliforms in coastal bathing waters of temperate and tropical seas and is designed for use in the sanitary surveillance of bathing beaches. It is based on the Multiple-Tube Fermentation Most Probable Number Test and can be used as an alternative to the Membrane Filtration Culture Method. Whether the Membrane Filtration Culture Method is preferred to the Multiple-Tube Fermentation Most Probable Number Test depends on local conditions and user preference. In general, the Membrane Filtration Culture Method is less labour-intensive and, because it concentrates bacteria from the sample before analysis, it is more suitable where low numbers of coliforms are expected. The Multiple-Tube Fermentation Most Probable Number Test is preferred when the sample contains large amounts of particulate matter that would interfere with interpreting the membrane filters after incubation.