can be confirmed as coliforms if they are inoculated in Lauryl Tryptose (LST), produce gas, and then inoculated in BGLB. If there is gas production in the BGLB tubes, the test is positive for the presence of coliform bacteria. See also Bacteriological water analysis Coliform index Fecal coliform Indicator bacteria Pathogenic Escherichia coli References Bacteria Foodborne illnesses Water quality indicators