Characterization of sludges - Detection and enumeration of Escherichia coli in sludges, soils, soil improvers, growing media and biowastes - Part 1: Membrane filtration method for quantification
This part of the CEN Technical Report specifies a membrane filtration procedure for the quantitative detection, by culture of individual colonies on chromogenic agar media, of Escherichia coli. in sludges, soils, soil improvers, growing media and biowastes. This part of the Technical Report is not suitable for materials whose treatment will significantly reduce bacterial levels to less than 10 viable E. coli per g wet weight, such as lime
addition, drying or pasteurisation. A liquid enrichment and most probable number estimation method may be suited for such purpose.
This membrane filtration method is not appropriate for enumeration and detection of other coliform bacteria without modifications to the chromogenic agar media.
It is suitable to evaluate the log reduction of E.coli through treatment, as well as the quality of the end product.
This method is for materials with dry residues less than 20 %. For materials with dry residues greater
than 20 % and low numbers of E. coli, CEN/TR 15214-2 and CEN/TR 15214-3 should be used.