022143P1 Macconkey Agar




For isolating lactose-fermenting Gram-negative enteric bacilli.

Peptones are sources of nitrogen and other nutrients. Lactose is a fermentable carbohydrate. When lactose is fermented, alocal pH drop around the colony causes a color change in the pH indicator (neutral red) and bile precipitation. Bile salts,bile salts no. 3, oxgall and crystal violet are selective agents that inhibit growth of gram-positive organisms. Agar is the solidifying agent.

Formulation(per liter):

Pancreatic Digest of Gelatin17.0 g
Peptones (meat and casein)3.0 g
Lactose Monohydrate10.0 g
Sodium Chloride5.0 g
Bile Salts1.5 g
Agar13.5 g
Neutral Red30.0 mg
Crystal Violet1 mg
Final pH7.1±0.2

How to use:
1.Suspend 50 g in 1 L of distilled or deionized water. Heat to boiling to dissolve completely. Autoclave at 121°C for 15 minutes.

2.Transfer 1 mL of Soybean–Casein Digest Broth to 100 mL of MacConkey Broth, and incubate at 42 to 44 for 24 to 48 hours. Subculture on a plate of MacConkey Agar at 30 to 35 deg.C for 18 to 72 hours.

Quality control:

ItemThe name and number of strainPR/GReaction
Growth rateE.Coli ATCC8739PR≥0.7Rose-red
Characteristic differenceProteus mirabilis CMCC(b)49005PR≥0.7Colorless,
no swarming
SelectiveStaphylococcus aureus ATCC6538G≤1

Storage: Keep container tightly closed, store in a cool, dry place, away from bright light. Storage period of three years.

Specifications: 250g/bottle

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