HCM161 MacConkey Agar NO.3
$28-37
Product No.Product CategorySpecificationHCM161Dehydrated Culture Medium500g/bottle Intended Use For the differentiation between lactose and nonlactose fermenters with the inhibition of Gr……
Introduction
| Product No. | Product Category | Specification |
| HCM161 | Dehydrated Culture Medium | 500g/bottle |
Intended Use
For the differentiation between lactose and nonlactose fermenters with the inhibition of Gram-positive cocci from clinical samples (e.g. faecal, blood, bile, pus, skin, mouth, etc.). Can also be used for testing food and water samples.
Principle and Interpretation
Peptone provides nitrogenous and carbonaceous compounds amino acids, vitamins and other essential growth nutrients. The selective action of this medium is attributed to crystal violet and bile salts, which are inhibitory to most species of gram positive bacteria. Gram-negative bacteria usually grow well on the medium and are differentiated by their ability to ferment lactose. Lactose fermenting strains grow as red or pink and may be surrounded by a zone of acid precipitated bile. The red colour is due to production of acid from lactose, absorption of neutral red and a subsequent colour change of the dye when the pH of medium falls below 6.8. Lactose non-fermenting strains, such as Shigella and Salmonella are colourless and transparent and typically do not alter appearance of the medium.
Formulation
| Ingredients | /liter |
| Peptone | 20.0g |
| Lactose | 10.0g |
| Sodium chloride | 5.0g |
| Bile salts NO.3 | 1.5g |
| Neutral red | 0.03g |
| Crystal violet | 0.001g |
| Agar | 15.0g |
| pH7.1±0.2 at 25°C | |
Preparation
Suspend 51.5g in 1 liter of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes .Cool to 50°C. Mix well and pour into sterile containers.
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Quality Control
Cultural characteristics observed after incubation at 35-37°C for 24 hours
| Quality control strains | Growth | Characteristics |
| Escherichia coli ATCC25922 | Good, PR≥0.7 | Pink colonies bile precipitation |
| Salmonella typhimurium ATCC14028 | Straw colonies | |
| Proteus mirabilis ATCC29906 | Straw colonies, slight/ no swarming | |
| Shigella sonnei ATCC25931 | Straw colonies | |
| Staphylococcus aureus ATCC6538 | G≤1 | Inhibition |
| Enterococcus faecalis ATCC29212 |
Storage and Shelf Life
2-30°C，Keep container tightly closed, avoid direct sunlight. Use before expiry date on the label.
Precautions
1. When weighing the dehydrated medium, please wear masks to avoid causing respiratory system discomfort 2. Keep container tightly closed after using to prevent clumping.
Waste Disposal
Microbiological contamination was disposed by autoclaving at 121°C for 30 minutes.
