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EU Drinking Water Directive reference methods for enumeration of total coliforms and Escherichia coli compared with alternative methods
Author(s) -
Schets F.M.,
Nobel P.J.,
Strating S.,
Mooijman K.A.,
Engels G.B.,
Brouwer A.
Publication year - 2002
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2002.01075.x
Subject(s) - enumeration , escherichia coli , microbiology and biotechnology , enterobacteriaceae , biology , environmental science , chemistry , mathematics , combinatorics , genetics , gene
Aims: The reference methods for enumeration of total coliforms and Escherichia coli as stated in the European Drinking Water Directive were compared with alternative methods. Methods and Results: Laboratories used the reference method on Lactose TTC agar (LTTC), the Colilert ® /18 system, Laurysulphate Agar (LSA), Chromocult ® Coliform Agar and the E. coli Direct Plating (DP) method. They enumerated more total coliforms on LTTC than on LSA. Conclusions: LTTC is suitable for analysis of very clean water samples only, due to heavy background growth. Colilert ® /18 is a good alternative but it enumerates a broader group of total coliforms, resulting in higher counts. The DP method appeared to be the best choice for enumeration of E. coli because Colilert ® /18 produces lower counts and false‐negative results. Significance and Impact of the Study: This study shows the limitations of the EU reference method on LTTC due to lack of selectivity and suggests alternative methods for the enumeration of total coliforms and E. coli .