Merck
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M7408

Millipore

MacConkey Agar

NutriSelect® Basic, suitable for microbiology

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Synonym(s):
Enteric bacteria selective medium, MacConkey′s medium
EC Number:
MDL number:
eCl@ss:
42040102
NACRES:
NA.74

sterility

non-sterile

Quality Level

form

powder

packaging

bottle of 250 g
bottle of 500 g

manufacturer/tradename

NutriSelect® Basic

color

light yellow

application(s)

agriculture
environmental
food and beverages
pharmaceutical
water monitoring

microbiology

suitability

Citrobacter spp.
Escherichia coli
Gardnerella spp.
coliforms

General description

MacConkey Agar is used for the isolation, identification, and enumeration of lactose fermenting and lactose non-fermenting enteric bacteria.The media is accepted by the Standard Methods for the Examination of milk and dairy Products and pharmaceutical preparations. Peptone in the media provides nitrogenous and carbonaceous compounds, long-chain amino acids, vitamins, and other essential growth factors. Lactose is the fermentable sugar that causes acid production and a color change of the indicator when the pH of the medium falls below 6.8. Sodium chloride maintains the osmotic equilibrium. 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 form red or pink colonies and are surrounded by a zone of acid-precipitated bile. Lactose non-fermenting strains, such as Shigella and Salmonella, form colorless, transparent colonies and typically do not alter the appearance of the medium.

Application

MacConkey Agar is a differential plating medium recommended for the detection and isolation of coliforms and intestinal pathogens from stool, urine, water, and other material.

Biochem/physiol Actions

MacConkey Agar is considered as a selective and differential media. It is useful in differentiating between the lactose fermenting and non-lactose fermenting bacteria. Thus, it is useful in the isolation of gram negative bacteria. Primary plating medium is used to differentiate members of the coliform group.

Features and Benefits

NutriSelect® Basic are powdered culture media offering
  • Quality control with basic growth promotion test
  • Quality assurance acc. to ISO 9001
  • Cost-efficient powdered media

Preparation Note

Suspend 50 g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilize by autoclaving at 121°C for 15 minutes. Pour into sterile petri plates. Dry the surface of the gel before inoculation.

Analysis Note

Microbiologically tested.

Footnote

We offer two media types: the superior granulated GranuCult® and the cost-efficient powdered NutriSelect® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany
NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany

Storage Class Code

11 - Combustible Solids

WGK

WGK 1

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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