TETRATHIONATE BROTH (BASE)

General description

GranuCult^® plus Tetrathionate broth (base) is a selective enrichment medium for Salmonella. Tetrathionate and excess thiosulfate suppress coliform microorganisms and other accompanying bacteria, whereas all tetrathionate-reducing bacteria (e.g., Salmonella and Proteus) can multiply in this medium. Calcium carbonate neutralizes the acidic tetrathionate decomposition products. Bile salts inhibit all microorganisms which do not normally live in the intestine. The United States Pharmacopeia recommends the addition of brilliant green to suppress the Gram-positive microbial flora. The resulting culture medium has a strong inhibitory effect and is therefore, sometimes better to omit the brilliant green to obtain satisfactory yields of salmonellae. Proteus can be suppressed by adding 0.04 g novobiocin/liter.

Application

GranuCult^® plus Tetrathionate broth (base) is suitable for the selective enrichment of salmonellae from various materials.

Analysis Note

Appearance (clearness): milky-turbid
Inoculum on reference medium (Salmonella typhimurium ATCC 14028 (WDCM 00031)): 10 - 100
Inoculum on reference medium (Escherichia coli ATCC 25922 (WDCM 00013)): ≥ 1E+04
Enrichment from a mixed inoculum after 24 hours (Escherichia coli ATCC 25922 (WDCM 00013)): ≤ 5 %
Enrichment from a mixed inoculum after 24 hours (Salmonella typhimurium ATCC 14028 (WDCM 00031)): ≥ 95 %
Growth (Salmonella typhimurium ATCC 14028 (WDCM 00031)): +
Growth (Escherichia coli ATCC 25922 (WDCM 00013)): inhibited
Inoculum on reference medium (Salmonella typhimurium ATCC 13311 (WDCM 00121)): 10 - 100
Inoculum on reference medium (Salmonella Abony NCTC 6017): 10 - 100
Growth (Salmonella typhimurium ATCC 13311 (WDCM 00121)): +
Growth (Salmonella Abony NCTC 6017): +
Detection with Brolacin agar.

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