Fluorocult VRB Agar

Fluorocult^® VRB Agar

EMD Cat. No. 1.04030.0500

500 g

Additives

EMD Cat. No.	Product	Pack Size
1.13203.0001	UV Lamp (366 nm)	1 ea

Typical Composition (g/liter)

Quality Control

Mode of Action
This medium is used for the detection and enumeration of coliform bacteria, in particular E. coli. Crystal violet and bile salts largely inhibit the growth of Gram-positive accompanying bacterial flora. Lactose-postitive colonies show a color change to red of the pH indicator. E. coli colonies schow a fluorescence under UV light.

Preparation
Suspend 39.6 g in 1 liter of purified water and heat in a boilling waterbath or in free flowing steam with frequent stirring until completely dissolved. Afterwards do not boil for more than 2 minutes.

Do not autoclave! Do not overheat!

pH: 7.4 ± 0.2 at 25 °C.
The plates are clear and dark red.

Experimental Procedure and Evaluation
Inoculate the medium in the usual way and incubate for 18-24 hours at 35 °C.
Lactose-negative Enterobacteriaceae are colorless. Lactose-positive colonies are red and often surrounded by a turbid zone due to the precipitation of bile acids.

Fluorescence is noted with a UV lamp: light blue fluorescing colonies denote E. coli.

Quality control

Test strains	Growth	Colony color	Precipitate	MUG
Escherichia coli ATCC 11775	good / very good	red	+	+
Enterobacter aerogenes ATCC 13048	good / very good	red	+	-
Salmonella gallinarum NCTC 9240	good / very good	colorless		-
Shigella flexneri ATCC 29903	good / very good	colorless		-
Yersinia enterocolitica ATCC 9610	fair / very good	colorless		-
Staphylococcus aureus ATCC 6538	none
Micrococcus luteus ATCC 9341	none
Lactococcus lactis spp. lactis ATCC 19435	none
Bacillus cereus ATCC 11778	none
Lactobacillus plantarum ATCC 14917	none / poor

Typical Composition (g/liter)
Peptone from meat 7.0; yeast extract 3.0; sodum chloride 5.0; lactose 10.0; neutral red 0.03; bile salt mixture 1.5; crystal violet 0.002; agar-agar 13.0; 4-methylumbelliferyl-β-D-glucuronide 0.1.