Tetrathionate Crystal-violet Enrichment Broth acc. to PREUSS

Tetrathionate Crystal Violet Enrichment Broth PREUSS

EMD Cat. No. 1.05173.0500

500 g

Medium proposed by PREUSS (1949) for the selective enrichment of Salmonella from meat, foodstuffs etc.

This culture medium complies with the specifications prescribed in the Fleischbeschaugesetz (German Meat Inspection Law) and the Einfuhruntersuchungsverordnung (German Regulations for the Examination of Imported Goods).

Mode of Action	Preparation
Experimental Procedure and Evaluation	Quality Control
Typical Composition (g/liter)	Literature

Mode of Action
Tetrathionate and crystal violet largely inhibit the entire accompanying bacterial flora including Shigella.

Preparation
Suspend 35 g/liter, heat gently, if necessary (max. 50 °C), dispense into suitable containers.
Do not autoclave.
pH: 6.5 ± 0.2 at 25 °C.
The prepared broth is clear and violet.

The culture medium is not stable and must therefore be prepared always fresh.

Experimental Procedure
Inoculate the broth with the sample material
Incubation: 18-24 hours at 35-37 °C.

Spread material from the resulting cultures on selective culture media.

Quality control

	Inoculum	Growth	after
Test strains		6 hours	20 hours
Escherichia coli ATCC 25922	approx. 99 %	<= 50 %	<= 10 %
Salmonella typhimurium ATCC 14028	approx. 1 %	>= 50 %	>= 90 %

Typical Composition (g/liter)
Peptone from meat 4.3; peptone from casein 4.3; sodium chloride 6.4; potassium tetrathionate 20.0; crystal violet 0.005.

Literature

Deutsches Fleischbeschaugesetz: Aufführungsbestimmungen A über die Untersuchung und gesundheitspolizeiliche Behandlung der Schlachttiere und des Fleisches bei Schlachtungen im Inland, Anlage 1 zu § 20 Abs. 4: Vorschriften über die bakteriologische Fleischuntersuchung.
Verordnung über die Untersuchung des in das Zollgebiet eingehenden Fleisches (Einfuhruntersuchungsverordnung). Anlage 1 zu § 20 Abs. 1: Untersuchungsverfahren.
PREUSS, H.: Über eine neue Tetrathionat-Anreicherung. - Z. Hyg., 129; 187-214 (1949).