TETRATHIONATE BROTH

Tetrathionate Broth is a selective enrichment medium used for the isolation and recovery of Salmonella species from foods and other pathological materials. The formulation is based on the medium originally described by Mueller and is prepared according to the requirements of the Indian Pharmacopoeia. It is also specified as an enrichment medium for Salmonella in recognized microbiological examination methods for foods, water and wastewater.
The selective action of the medium depends on the combined activity of thiosulphate and tetrathionate, which is formed through the addition of iodine and potassium iodide. These components suppress the growth of many accompanying coliform organisms while allowing microorganisms capable of reducing tetrathionate to multiply. The medium can also aid in the recovery of Salmonella cells that may become injured during food processing and may not readily form colonies on selective plating media.
Yeast extract, meat extract B and peptone contain nutrients, vitamins and growth factors necessary for the growth of the microbes. Calcium carbonate neutralizes acidic products that are formed during the decomposition of tetrathionate, and sodium chloride provides the osmotic balance. Sodium thiosulphate also helps to neutralize residual halogens toxicity when these are in the test samples.

Tetrathionate Broth is used for selective isolation of Salmonellae from foods and other pathological materials