Collect a sterile sample from the source to be tested
Use a selective culture medium for E. coli
Incubate the sample at the recommended temperature and time
Check for characteristic colony appearance
Perform a Gram stain to confirm gram-negative rods
Run a lactose fermentation test
Use an indole test
Use a methyl red test
Use a citrate utilization test
Use an oxidase test
Perform a biochemical identification panel
Use a rapid antigen test if available
Use PCR or qPCR for genetic confirmation
Test water samples with a coliform/E. coli test kit
Send the sample to a certified laboratory for confirmation