MacConkey Broth W/Neutral Red – HX-Media
Product Overview
MacConkey Broth with Neutral Red is a selective and differential enrichment medium formulated for the isolation, detection, and presumptive enumeration of coliform bacteria from a wide range of samples including drinking water, wastewater, food products, dairy samples, and pharmaceutical preparations.
MacConkey Broth is specifically designed to promote the growth of Gram-negative enteric organisms belonging to the family Enterobacteriaceae, while effectively inhibiting Gram-positive bacteria through the incorporation of bile salts, which mimic the inhibitory conditions of the intestinal environment.
MacConkey Broth contains lactose as the primary fermentable carbohydrate, enabling differentiation of microorganisms based on their ability to ferment lactose. Coliform organisms metabolize lactose to produce organic acids and gas, leading to a drop in pH. This pH change is detected by the neutral red indicator, which shifts from its original pale yellow color to distinct red or pink, indicating a positive lactose fermentation reaction.
In addition to color change, gas production is an essential confirmatory parameter and is detected using inverted Durham tubes, making this medium highly suitable for Most Probable Number (MPN) analysis, a widely accepted statistical method for estimating microbial density in water and food samples.
MacConkey Broth with Neutral Red is extensively used in quality control laboratories, environmental monitoring, public health testing, and food safety analysis, complying with standard microbiological protocols such as APHA, ISO, BIS, and FDA guidelines. Its high sensitivity, reproducibility, and ease of interpretation make it a preferred medium for routine and regulatory testing.
🔬 Key Features
- Highly selective for Gram-negative enteric bacteria
- Differential based on lactose fermentation with clear color change
- Neutral red indicator provides rapid visual confirmation
- Supports acid and gas detection simultaneously
- Ideal for MPN testing and coliform enumeration
- Compatible with international testing standards (APHA, ISO, BIS)
- Provides consistent and reproducible results
🎯 Applications
- Water quality testing (drinking water, wastewater, surface water)
- Most Probable Number (MPN) analysis for coliform estimation
- Food and beverage microbiology testing
- Dairy industry for hygiene and contamination monitoring
- Environmental and sanitation studies
- Pharmaceutical microbiological quality control
🧪 Composition (Typical)
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Peptone: 20.0 g
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Lactose: 10.0 g
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Bile Salts: 5.0 g
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Sodium Chloride: 5.0 g
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Neutral Red: 0.01 g
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Final pH (25°C): 7.4 ± 0.2
🛠️ How to Use
- Suspend the specified amount of dehydrated medium in distilled water.
- Mix MacConkey Broth thoroughly and heat gently to dissolve completely.
- Dispense into test tubes containing inverted Durham tubes.
- Sterilize by autoclaving at 121°C for 15 minutes.
- Allow to cool to room temperature.
- Inoculate with the sample (as per MPN or direct inoculation method).
- Incubate at 35–37°C for 24–48 hours.
⏳Storage and Shelf Life
- Store dehydrated medium at 10–30°C, in a dry place away from direct light
- Keep container tightly closed to prevent moisture absorption
- Prepared broth should be used immediately or stored at 2–8°C for short duration
- Shelf life: Up to 3 years in unopened dehydrated form
👍 Ideal For
✔ Coliform detection in water and food.
✔ MPN-based quality testing.
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