USGS Ohio Water Science Center
mFC agar method for fecal coliforms. Updated January 2007
The mFC agar method is a one-step membrane-filtration method for enumeration of fecal coliforms. See Britton and Greeson (1987) for a step-by-step description of the method. This method can be done in the field or laboratory.
Lactose utilization (blue color) is the basis for identification of fecal coliforms.
We recommend that for new monitoring programs, E. coli be used instead of fecal coliforms, whenever possible. Fecal coliforms may be from fecal or nonfecal sources. E. coli is natural inhabitant of the gastrointestinal tract of warmblooded animals and is direct evidence of fecal contamination. The mFC method, however, can be used for comparisons with historical data.
Pre-poured plates can be purchased from Microbiology International (800/396-4276, Cat 215166 (30 plates)) or from Fisher Scientific (Cat B4392345 (10 plates)). Rosolic acid is incorporated in the prepoured plates and does not have to be added.
Use phosphate buffered dilution water and 0.45 mm membrane filters (0.65 mm filters are still acceptable). Buffer can be purchased from Hardy Diagnostics (800/266-2222, Cat D699 (99mL) or Cat U193 (500mL)). See buffer preparation (Appendix M).
U.S. Environmental Protection Agency, 1989, Drinking water—National Primary Drinking Water Regulations—total coliforms (including fecal coliforms and E. coli): Federal Register, vol. 54, no. 124, p. 27544.
U.S. Environmental Protection Agency, 2004, Final rule, water quality standards for coastal and Great Lakes recreation waters: Title 40, part 131, 67218 p.
NWIS PARAMETER CODES:
31625 Fecal coliforms, 0.7 mm, colonies per 100 mL
Parameter code 31616 provides a better description of the method and is to be used for current work.