Tetrathionate Broth | DM219S

Tetrathionate Broth | DM219S

A selective enrichment medium for the detection and isolation of salmonellae in faeces, water and food.

This selective enrichment broth for the detection and isolation of salmonellae was originally formulated by Mueller in 1923.1 Tetrathionate is produced by the addition of iodine to thiosulphate. The ability of salmonellae to reduce tetrathionate and the inhibitory effect of tetrathionate on most other enteric organisms makes the broth selective. The bile salts present also act to inhibit other enteric organisms.

Directions

1. Suspend by swirling 46g in 1 litre of distilled or deionised water.
2. Boil the suspension, cool to below 45°C and add 20ml of iodine solution.
3. Mix well and distribute 10ml amounts in test tubes.

Technical Formula

In Use

Suspend, by thorough mixing, approx.-imately 2g of the material to be tested in 10ml of Tetrathionate Broth. Incubate for 12 to 24 hours then use to inoculate plates of differential culture media (Bismuth Sulphite Agar, DM103 and DM103s, Desoxycholate Citrate Agar DM130, XLD Agar DM230 etc).

N.B.
After the addition of iodine the medium should be used on the same day. The base only will keep for several weeks at 4°C.

Iodine solution