Improved methods for determining the most probable number of Bacterium coli and of Streptococcus faecalis.

摘要: Three methods have been investigated for determining Most Probable Numbers, using lactose-bile salts broth Bacterium coli and glucose-yeast extract-azide Streptococcus faecalis . In the ‘direct’ method inoculated tubes of medium are incubated directly in a water-bath, at 44° C. Bact. or 45° Str. ‘subculture’ primary incubation 37° is followed by subculture positive to fresh media which higher temperature. ‘resuscitation’ each divided into 2 parts. The inoculum mixed, McCartney bottles tubes, with first part medium, containing sugar peptone, mixture held 1–2 hr. resuscitate organisms weakened age long immersion water. second bile azide, then added 44 With samples polluted waters gives significantly counts than but not coli. results both organisms, it requires less time completion, specific organism concerned. These were obtained 0.003% brom-cresol purple as indicator; neutral red was found be inhibitory. This paper published permission Department Scientific Industrial Research.