DM50066 | Macconkey Agar

CAS Number

Formula

Weight

Usages:
For isolating lactose-fermenting Gram-negative enteric bacilli.
 
Principle:
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 Gelatin 17.0 g
Peptones (meat and casein) 3.0 g
Lactose Monohydrate 10.0 g
Sodium Chloride 5.0 g
Bile Salts 1.5 g
Agar 13.5 g
Neutral Red 30.0 mg
Crystal Violet 1 mg
Final pH 7.1±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 35deg.C for 18 to 72 hours.
 
Quality control:
            

Item The name and number of strain PR/G Reaction
Growth rate E.Coli ATCC8739 PR≥0.7 Rose-red
Characteristic difference Proteus mirabilis CMCC(b)49005 PR≥0.7 Colorless,
no swarming
Selective Staphylococcus aureus ATCC6538 G≤1 -
 

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

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