MACCONKEY AGAR (W/ 0.15% BILE SALTS, CV & NR) A1- Quality | HX-MEDIA

MACCONKEY AGAR (W/ 0.15% BILE SALTS, CV & NR) | HX-MEDIA

Product Overview

MacConkey Agar is a selective and differential culture medium specially formulated for the isolation, cultivation, and differentiation of Gram-negative enteric bacilli from clinical, food, water, pharmaceutical, and environmental samples. The medium was originally developed by Alfred Theodore MacConkey Agar and remains one of the most widely used media in microbiology laboratories worldwide.

This formulation contains 0.15% bile salts, crystal violet, and neutral red indicator, which together provide excellent selectivity and differentiation characteristics. The presence of bile salts and crystal violet suppresses the growth of most Gram-positive organisms, thereby allowing selective growth of Gram-negative bacteria, particularly members of the Enterobacteriaceae family.

MacConkey Agar differentiates microorganisms based on their ability to ferment lactose. Organisms capable of lactose fermentation produce organic acids, lowering the pH of the surrounding medium. This acidic condition causes the neutral red indicator to change color, resulting in the formation of pink to red colonies, often surrounded by a zone of precipitated bile salts. Non-lactose fermenting organisms utilize peptones instead of lactose, producing alkaline end products that keep the colonies colorless or transparent.

Lactose→FermentationAcid Production→Decrease in pH→Pink/Red Colonies\text{Lactose} \xrightarrow{\text{Fermentation}} \text{Acid Production} \rightarrow \text{Decrease in pH} \rightarrow \text{Pink/Red Colonies}LactoseFermentation​Acid Production→Decrease in pH→Pink/Red Colonies

MacConkey Agar supports the growth of a wide variety of Gram-negative organisms such as Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Salmonella, and Shigella. Lactose fermenters like E. coli typically produce bright pink colonies, while non-lactose fermenters such as Salmonella and Shigella appear colorless or pale.

MacConkey Agar is extensively used in:

• Clinical microbiology laboratories for detection of enteric pathogens
• Water and wastewater testing for coliform organisms
• Food and dairy microbiology
• Pharmaceutical quality control
• Environmental monitoring
• Research laboratories

MacConkey Agar demonstrates excellent batch-to-batch consistency, reliable differentiation capability, and high selectivity, making it suitable for routine microbiological examination and quality assurance testing.

🔬 Key Features

• Selective for Gram-negative enteric bacteria
• Differentiates lactose fermenters from non-fermenters
• Contains 0.15% bile salts for enhanced selectivity
• Crystal violet inhibits Gram-positive organisms
• Neutral red indicator provides clear colony differentiation
• Excellent medium for routine microbiological analysis
• Produces distinct colony morphology for easy identification

🎯 Applications

• Isolation of enteric Gram-negative bacteria
• Detection of coliform organisms in water and food testing
• Clinical diagnostic microbiology
• Pharmaceutical microbiology testing
• Environmental monitoring
• Identification of lactose fermenting bacteria like E. coli
• Isolation of pathogens such as Salmonella and Shigella

🧪 Composition (Typical)

• Peptone : 17.0
• Proteose Peptone : 3.0
• Lactose : 10.0
• Bile Salts : 1.5
• Sodium Chloride : 5.0
• Neutral Red : 0.03
• Crystal Violet : 0.001
• Agar : 13.5

Final pH: 7.1 ± 0.2 at 25°C

🛠️ How to Use

1. Suspend the required quantity of medium in purified water.
2. Heat with gentle stirring to dissolve completely.
3. Sterilize by autoclaving at 121°C for 15 minutes.
4. Cool to 45–50°C and pour into sterile Petri plates.
5. Allow medium to solidify before inoculation.
6. Incubate inoculated plates at 35–37°C for 18–24 hours.

⏳ Storage & Shelf Life

• Store the dehydrated medium in a cool, dry place below 30°C.
• Keep container tightly closed and protected from moisture and direct sunlight.
• Prepared plates should be stored at 2–8°C.
• Use before the expiry date mentioned on the label for best performance.