Differentiation of non-faecal coliforms faecal coliforms
Elevated temperature test
Simultaneously with the confirmatory procedure using brilliant green lactose broth, transfer should be made from all positive presumptive tubes to EC broth medium.
The inoculated EC tubes are incubated at 45.5 oC for
24hours, and gas formation is recorded bacterial density is estimated from the tables of Run IMViC Test
and the MPN.
Streak E.M.B agar or Endo agar from each positive tubes in a way to obtain discrete colonies and incubate for 18-24 hours at 35 oC. Perform indole, methyl red, v-p and citrate tests (IMViC).
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Classification of Colifroms by IMViC test
Type Typical E.coli Atypical E.coli Typical intermediate Atypical intermediate Typical E.aerogenes Atypical E.aerogenes