Description

INTENDED USE

m FC Agar is used with Rosolic Acid in cultivating and enumerating fecal coliforms by the membrane filter technique at elevated temperatures.

SUMMARY AND EXPLANATION

Geldreich et al. formulated a medium to enumerate fecal coliforms (MFC) using the membrane filter (MF) technique without prior enrichment. Fecal coliforms (i.e., those found in the feces of warm-blooded animals) are differentiated from coliforms from environmental sources by their ability to grow at 44.5 ± 0.5°C.

Many “standard methods” membrane filtration procedures specify m FC medium for testing water. The American Public Health Association (APHA) specifies m FC medium and incubation at 44.5 ± 0.5°C in the fecal coliform membrane filter procedure, the delayed-incubation fecal coliform procedure and the two-layer agar method for recovering injured fecal coliforms. AOAC International specifies m FC Agar for detecting total coliforms and fecal coliforms in foods.

The U. S. Environmental Protection Agency specifies using m FC medium in fecal coliform methods for testing water by the direct MF method or the delayed-incubation MF method.

PRINCIPLE

m FC Agar and m FC Broth Base contain peptones as sources of carbon, nitrogen, vitamins and minerals. Yeast extract supplies B-complex vitamins that stimulate bacterial growth. Lactose is a carbohydrate. Bile Salts No. 3 inhibits growth of gram-positive bacteria. m FC Agar contains agar as the solidifying agent. The differential indicator system combines aniline blue and rosolic acid.

Colonies of fecal coliforms are blue; non-fecal coliforms and other organisms are gray to cream-colored.