Slanetz and Bartley Medium is recommended for detection and enumeration of faecal Streptococci by membrane filtration technique. The medium is highly selective for Enterococci. Sodium azide inhibits gram-negative organisms. It does not conatin TTC. If desired TTC can be added to medium to enhance detection of colony. Triphenyl Tetrazolium Chloride is reduced to the insoluble formazan inside the bacterial cell forming dark red-coloured colonies. Enterococcus faecalis grows luxurianlly as red or maroon colonies while Escherichia coli is inhibited on this medium.