Merck Enterococcus Selective Agar, also known as Slanetz and Bartley Agar or m-Enterococcus Agar, is a selective and differential culture medium designed for the enumeration and detection of enterococci in water, sewage, food, and environmental samples. This formulation complies with ISO 7899-2:2000, making it suitable for standardized water quality monitoring and bioburden assessments.

The medium supports the growth of Enterococcus spp. and Group D streptococci, enabling clear differentiation through color reactions mediated by 2,3,5-triphenyltetrazolium chloride (TTC). Enterococcal colonies typically appear red, maroon, or pink due to TTC reduction, aiding rapid and reliable identification.

Ordering Information

Key Features

• Selective and differential medium for Enterococcus spp.
• Complies with ISO 7899-2:2000 for water analysis.
• Suitable for membrane filtration and direct plating methods.
• Ideal for bioburden testing, food microbiology, environmental monitoring, and clinical testing.
• Powdered NutriSelect® Basic format (cost-efficient option).
• Clear chromogenic-like reaction using TTC for reliable colony differentiation.

Composition (per Liter)

• Tryptose — 20 g
• Agar — 10 g
• Yeast extract — 5 g
• Disodium hydrogen phosphate monohydrate — 4 g
• D(+)-Glucose — 2 g
• Sodium azide — 0.4 g
• 2,3,5-Triphenyltetrazolium chloride (TTC) — 0.1 g

This composition ensures selectivity against Gram-negative organisms while supporting robust growth of enterococci.

Properties & Specifications

Applications

• Water monitoring (ISO 7899-2 membrane filtration)
• Environmental microbiology
• Bioburden and contamination testing
• Food and beverage quality control
• Clinical and diagnostic microbiology
• Detection of enterococci in sewage, surface water, drinking water, and food samples

Also cited for use in enumeration of sulphite-reducing Clostridium spores and differentiation of Group D faecal streptococci in oysters.

Preparation Note

1. Dissolve 42 g of medium in 1 L of distilled water.
2. Sterilize in a steamer without pressure for 30 minutes.
3. Do not autoclave.
4. Pour plates.

This gentle sterilization preserves medium selectivity and TTC reaction integrity.

Additional Notes

• Available in both GranuCult® (granulated, superior quality) and NutriSelect® (powdered, economical) formats.
• Quality designations: Basic, Plus, Prime, depending on QC and regulatory compliance level.

Merck Enterococcus Selective Agar (NutriSelect® Basic) is a reliable, ISO-compliant medium for detection and enumeration of enterococci across water, environmental, clinical, and food-testing laboratories. Its proven selectivity, clear visual colony differentiation, and standard preparation protocol make it a trusted choice for routine microbiological surveillance and regulatory testing.