BacterPlate™ MacConkey Agar (MC)

Ready-to-use medium on 90mm plates is a selective medium for isolating easily cultured Gram-negative bacteria.
Code: 05018
Packaging: 10 plates/ box or as per customer request.
Storage Conditions: 2–8°C.
Transportation: Ambient temperature.
Shelf Life: 04 months from the date of manufacture.

INTENDED USE

BacterPlate™ MacConkey Agar is a selective medium for the isolation of enterobacteria in water, food, pharmaceutical products and biological samples of animal origin and in cosmetic products.
The typical composition corresponds to that defined in the EU Pharmacopeia and in the standards NF EN ISO 21567 and NF EN ISO 21150.
The packaging with semi-permeable Cellophane film helps balance the humidity of the environment during storage.

PRINCIPLES

Bile salts and crystal violet inhibit the growth of Gram-positive bacteria. The dye inhibits primarily the development of enterococci and staphylococci.
The fermentation of lactose to acid is revealed in the presence of neutral red by the formation of red or pink colonies.
Lactose-negative colonies form colorless colonies.

1.Detection of Escherichia coli (harmonized chapters of the Pharmacopieae)

Dry the plates in an incubator, covers partially removed.
Inoculate the enrichment broth (MacConkey broth) onto a BacterPlate™ MacConkey Agar.
Incubate at 30 – 35°C for 18 to 72 hours.
The presence of colonies on the plates requires the completion of the confirmation tests for Escherichia coli.

2.Detection of Escherichia coli (Cosmetics, NF EN ISO 21150)

Dry the plates in an incubator, covers partially removed.
Inoculate the enrichment broth onto a BacterPlate™ MacConkey Agar
Incubate at 30 – 35°C for 24 to 48 hours.
The presence of brick-red colonies, with or without a zone of precipitated bile, requires the completion of confirmation tests for Escherichia coli

3.Detection of Shigella spp (Food microbiology, NF EN ISO 21567)

Dry the plates in an incubator, covers partially removed.
Inoculate the enrichment broth (for Shigella) onto a BacterPlate™ MacConkey Agar
Incubate at 37 ± 1°C for 20 to 24 hours.
If characteristic colonies are present, proceed with the necessary confirmation

RESULTS

Lactose-positive colonies form red colonies, surrounded by a halo due to bile salt precipitation. Lactose-negative colonies are colorless.
Escherichia coli forms brick-red colonies, with or without a surrounding bile salt precipitate.
Shigella sonnei are colorless to pale pink and translucid.
Other Shigella spp. are colorless and translucid.

BacterLab ensures the quality of each product batch by testing with ATCC reference strains

Microbial Standard and Incubation Conditions	Standard (P_R)
Incubation conditions after 18 – 24 hours, at 35 – 37°C, with inoculum ≤ 10²CFU/ mL
E. coli ATCC 35218	≥ 50 %
Incubation conditions after 24 – 48 hours, at 35 – 37°C, with inoculum ≤ 10³ – 10⁴ CFU/ mL
S. aureus ATCC 25923	Weak growth
S. flexneri ATCC 12022	Inhibited, no growth

For 1 liter of medium

Pancreatic digest of gelatin	17,0 g
Tryptone	1,5 g
Peptic digest of meat	1,5 g
Lactose	10,0 g
Bile salts	1,5 g
Sodium chloride	5,0 g
Neutral red	30,0 mg
Crystal violet	1,0 mg
Agar	13,5 g