Liofilchem Slanetz Bartley Agar Base

Slanetz Bartley Agar is a selective microbiological medium designed for the isolation, detection, and enumeration of intestinal enterococci in water, food, and other samples. This medium conforms to ISO 7899-2 for water quality analysis and meets the stringent requirements for microbiological examination of environmental and food samples. The medium is also known as m-Enterococcus Agar.

Key Features:

• Selective Detection: Designed to identify enterococci through the reduction of triphenyltetrazolium chloride (TTC) to red or maroon-colored formazan colonies.
• Broad Applications: Suitable for water quality testing, food safety monitoring, and microbiological quality control.
• Flexible Use: Available as a complete medium with TTC or as a base medium requiring supplementation with TTC 1% supplement.
• Inhibits Contaminants: Contains sodium azide, which inhibits Gram-negative bacteria and staphylococci, ensuring specificity for enterococci.

Applications:

1. Water Quality Testing:
   • Detection and enumeration of intestinal enterococci in drinking water, recreational water, and wastewater using membrane filtration.
2. Food Microbiology:
   • Direct plating to detect enterococci in food products, particularly in processed and raw foodstuffs.
3. Environmental Monitoring:
   • Used to assess microbial contamination in environmental samples, including soil and industrial effluents.

Composition:

Final pH: 7.2 ± 0.1 at 25°C

Method Principle:

• Tryptose and Yeast Extract: Provide essential amino acids, nitrogen, vitamins, and minerals for microbial growth.
• Glucose: Serves as a fermentable carbohydrate and energy source.
• Sodium Azide: Inhibits non-enterococcal organisms such as Gram-negative bacteria and staphylococci.
• TTC: A redox indicator that is reduced to red formazan, providing visual differentiation of enterococci colonies.

Preparation:

1. Dehydrated Medium with TTC:
   • Suspend 44.5 g of the powder in 1 liter of distilled or deionized water.
   • Heat to boiling until dissolved. DO NOT AUTOCLAVE.
   • Dispense 20 mL into sterile Petri dishes (90 mm diameter).
2. Dehydrated Medium without TTC:
   • Suspend 44.4 g of the base powder in 1 liter of distilled or deionized water.
   • Heat to boiling until dissolved. Cool to 45-50°C.
   • Add 10 mL of TTC 1% supplement and mix well before dispensing.

Test Procedure:

1. Water Testing:
   • Filter 100 mL of the sample through a 0.45 μm membrane filter.
   • Transfer the filter onto the surface of the medium.
2. Food and Other Samples:
   • Prepare serial dilutions as needed.
   • Spread 0.5 mL of the diluted sample onto the agar surface.
3. Incubation:
   • Incubate plates aerobically at 36 ± 2°C for 40-48 hours.

Result Interpretation:

• Typical Enterococci Colonies: Red, maroon, or pink colonies with TTC reduction to formazan.
• Confirmation:
  • Transfer colonies to Bile Aesculin Azide Agar and incubate at 44 ± 0.5°C for 2 hours.
  • Confirm intestinal enterococci by observing a brown to black color surrounding the colonies, indicating aesculin hydrolysis.

Storage:

• Dehydrated Medium:
  • Store at 10-30°C in a dry environment.
• Prepared Plates:
  • Store at 10-25°C, avoiding direct light.
  • Prevent quick temperature shifts to avoid condensation.
• Shelf Life:
  • Dehydrated medium: 4 years.
  • Ready-to-use plates: 6 months.
  • TTC Supplement: 1 year.

Quality Control:

Limitations:

• False negatives or inhibited growth may result from improper specimen handling or storage.
• Some strains may grow poorly due to nutritional requirements or environmental factors.
• Additional biochemical testing is required for definitive identification.

Ordering Information:

Slanetz Bartley Agar is an indispensable tool for microbiological testing in water, food, and environmental monitoring. Its selectivity, compliance with ISO standards, and adaptability for various testing methods make it a trusted medium for the accurate detection and enumeration of intestinal enterococci.