[Concentration methods for the determination of phages in water]

The object of the present study was to find a suitable method for the concentration of phages, especially from drinking water. Five possible ways have been tested. The technique of centrifugation utilizing a phage pre-adsorption to a particular substance (CaHPO4) yielded recoveries up to 42%, whereas no useful results by filtration through paper and membrane filters were obtained. The application of frits after phage pre-adsorption to CaHPO4 resulted in recoveries up to 80%. The method of choice evidently is that of chemical precipitation (flocculation), which allowed to recover up to 100% of the used phages. It requires the least material and technical expense, too.