KF Streptococcus Agar

Product information

Intended Use

KF Streptococcus Agar is used with triphenyltetrazolium chloride for the selective isolation and enumeration of fecal streptococci.

Product Summary and Explanation

KF Streptococcus Agar was developed by Kenner, Clark, and Kabler1 for the detection of fecal streptococci in surface waters. KF Streptococcus Agar is currently used in detecting fecal streptococci in water, foods, and other materials through the membrane filtration technique or pour plate method. Fecal streptococci are normal inhabitants in the intestines of humans and animals, and the presence of fecal streptococci can be used as an indication of fecal contamination. The presence of fecal streptococci is of value in determining pollution sources because certain fecal streptococci are host-specific.

KF Streptococcus Agar is recommended in standard methods for food and water testing.2,3

Principles of the Procedure
Enzymatic Digest of Animal Tissue is the nitrogen and carbon source in KF Streptococcus Agar. Yeast Extract provides vitamins and trace elements in the medium. Sodium Chloride is used to maintain the osmotic balance, and Sodium Glycerophosphate is a buffering agent. Maltose and Lactose are the fermentable carbohydrates and metabolized by most fecal streptococci. Sodium Azide is the selective agent, suppressing Gram-negative organisms. Acid formation is detected by Bromcresol Purple, and indicated by a color change from purple to yellow.

The supplement, 1% Triphenyltetrazolium Chloride (TTC), is a stain that is absorbed by actively metabolizing bacterial cells, resulting in the development of pink to red colonies.m-Endo Agar is used for the enumeration of coliforms in water by the membrane filtration method.