DIN EN ISO 9308-1:2017-09

The standard DIN EN ISO 9308-1 describes a microbiological method for the detection and enumeration of E. coli and coliform bacteria in water intended for human consumption. The method is based on membrane filtration, a subsequent subculture with different agar media and calculation of the number of target organisms in the sample. Due to the low selectivity of the differential agar medium, background growth can interfere with the reliable enumeration of E. coli and coliform bacteria, for example, in surface waters. This method is not suitable for these types of water. This part of ISO 9308 is specifically intended for drinking water, disinfected swimming pool water and other waters with a low bacterial count. Escherichia coli strains without the enzyme ß-glucuronidase, such as Escherichia coli O157, cannot be determined using this standard. The amendment corrects the incubation period in Clause 4, second paragraph, in 8.3, first paragraph and in 11.2 Table 1 and includes control strain WDCM 00087. This document has been prepared by Technical Committee ISO/TC 147 "Water quality" in collaboration with Technical Committee CEN/TC 230 "Water analysis", the secretariat of which is held by DIN (Germany). The responsible German committee is Subcommittee NA 119-01-03-03 UA "Mikrobiologie" ("Microbiology") of Working Committee NA 119-01-03 AA "Water examination" at DIN Standards Committee Water Practice (NAW).