A shortcut method for estimation of Escherichia coli in Sewage and receiving water.

A simplified method not yet widespread in Scandinavia for the assessment of E. coli in sewage and recipients with McConkey broth for 24 hours at 44 degrees C is recommended. 87 pairs of samples were examined at 37 degrees C and later at 44 degrees C, and directly at 44 degrees C. Also the reduction of the incubation time from 48 to 24 hours was studied. Direct incubation gave a loss of half a tube per sample, while shortening of the incubation period from 48 to 24 hours gave a smaller loss. The proposed alteration of the procedure for the examination of sewage and recipients means a slight loss of precision but this is more than compensated for by the possibility of examining more samples. The survey of the recipients can therefore be better and the control more effective.