<prompt> According to the WHO , what is the minimum bacteriological standard for drinking water -All the samples should not contain coliform organisms3 consecutive samples of water should not contain any coliforms3 coliforms in a 100 ml water1 coliform in a 100 ml water  <response>: Must not detect E. coli or thermotolerant bacteria in any 100 ml sample. Total coliform bacteria should be nil in any 100 ml sample Parks Textbook of Preventive and Social Medicine, 25th edition, Page No. 782 