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Thermo Scentific

Material Safety Data Sheet


Organisms this product works with:

Dehydrated Culture Media


Code: CM0029

Typical Formula*


`Lab-Lemco’ powder




Yeast extract


Sodium chloride


Calcium carbonate


Sodium thiosulphate


pH 8.0 ± 0.2

* Adjusted as required to meet performance standards 

Add 77g to 1 litre of distilled water and bring to the boil. Cool below 45°C and add 20ml of iodine solution. Mix well and tube in 10ml quantities. The prepared base will keep for several weeks at 4°C but should be used soon after the addition of the iodine solution.

Iodine Solution


6 grams

Potassium iodide

5 grams

Distilled water


Tetrathionate Broth is recommended for the selective enrichment method of isolating Salmonella typhi and other salmonellae from faeces, sewage, etc.

Organisms which reduce tetrathionate, such as salmonellae, flourish in the medium whilst many faecal organisms are inhibited1. Members of the Proteus group reduce tetrathionate and may consequently impair the value of this medium for the isolation of salmonellae; this disadvantage of the medium is largely overcome by the addition of 40µg of novobiocin to each millilitre of the incomplete medium before the addition of iodine2,3.

Inoculate the broth with about 2 grams of the specimen and mix thoroughly to disperse particulate matter. A loose cotton- wool plug may be passed down through the inoculated medium in order to carry gross particles to the bottom of the tube. Incubate for 12 to 24 hours at 35°C and then sub-culture on to Bismuth Sulphite Agar CM0201, SS Agar CM0099 or Desoxycholate Citrate Agar (Hynes) CM0227, etc.

The complete medium (with added iodine) should be used the same day as it is prepared, but the sterilised basal medium will keep for many weeks at 4°C. Jeffries2 showed that novobiocin, at a concentration of 40µg/ml in the medium, remained stable for at least 48 hours at 35°C, and for one month at room temperature.

This medium is frequently used in parallel with Selenite Broth Base CM0395.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium (without iodine solution) at 2-8°C.

Dehydrated medium: White, free-flowing powder
Prepared medium: Off white opaque suspension

Quality control

Positive control:

Expected results

Salmonella typhimurium ATCC® 14028 *

Good growth

Negative control:


Escherichia coli ATCC® 25922 *

Inhibited or no growth

* This organism is available as a Culti-Loop®

1. Knox R., Gell P. G. H. and Pollock M. R. (1942) J. Path. Bact. 54. 469-483.
2. Jeffries L. (1959) J. Clin. Path. 12. 568-571.
3. Buttiaux R., Catsaras M. and Verdant M. (1961) Ann. Inst. Pasteur de Lille 12. 13-18.

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