Selenite-F Broth was developed by Leifson to selectively inhibit normal gut bacteria like coliforms and allow for the recovery of Salmonella species from fecal specimens. The broth contains casein hydrolysate and lactose as nutrients, sodium phosphate to buffer the pH, and sodium selenite which inhibits many gram-positive and gram-negative bacteria. It is used to selectively enrich samples for Salmonella and some Shigella species. Proper handling of the toxic sodium selenite is required during preparation and use of the medium.

1. Selenite F Broth
Abhishek R. Indurkar
17PBT202
MTech Pharmabiotech

2. Selenite-F Broth
Selenite-F Broth was devised by
Leifson, who demonstrated that selenite
was inhibitory for coliforms and certain
other microbial species, such as fecal
streptococci, present in fecal specimens,
and thus, was beneficial in the recovery of
Salmonella species.
F in Selenite F Broth is Faeces, because it
is mostly used for the isolation of
Salmonella and Shigella from faecal
specimens.

3. Composition of Selenite
F Broth
Casein enzymic hydrolysate 5 gm/L
Lactose 4 gm/L
Sodium phosphate 10 gm/L
Sodium hydrogen selenite (NaHSeO3) 4 gm/L
pH 7.1 ± 0.2 @ 25°C

4. Principle
Casein enzymic hydrolysate provides nitrogenous
substances.
Lactose is a carbohydrate source.
Sodium phosphate maintains a stable pH and also
lessens the toxicity of selenite.
Sodium selenite inhibits many species of gram-
positive and gram-negative bacteria including
enterococci and coliforms.

5. Preparation
1. Add 4.0 gm sodium selenite powder to distilled water.
2. Add remaining 19.0 gm powder to above solution and bring volume to
1.0 litre.
3. Gently heat and bring to boiling.
4. Dispense into sterile test tubes, at least of a depth of 5 cm.
5. Sterilize in boiling water bath or at 0 psi pressure at 100°C for 10
minutes.
6. DO NOT AUTOCLAVE.
7. Cool to room temperature prior to use.

6. Quality Control on
Selenite F Broth
Positive control: Salmonella Typhimurium ATCC®
14028. Good Growth.
Negative control: Escherichia coli ATCC® 25922.
Inhibited or no growth.

7. Uses
1.Selenite F Broth is used as a selective enrichment for
the cultivation of Salmonella spp.
2.It is also used as an enrichment medium for the
isolation of some species of Shigella.
3.The broth is also recommended for the transport of
strains of Vibrio cholerae, because these organisms
can survive 2 to 5 days in Sodium Selenite Broth.

8. Limitations
1.Sodium hydrogen selenite (Sodium biselenite) is very
toxic, corrosive agent and causes teratogenicity.
Handle with great care. If there is contact with skin,
wash immediately with lot of water.
2.Due to nutritional variation, some strains may be
encountered that grow poorly or fail to grow on this
medium.

9. References
E&O Laboratories Ltd- Selenite F Broth (BM0360).
HiMedia Laboratories Pvt. Ltd.- Selenite Broth
(Selenite F Broth) (Twin Pack) (M052).
Mast Diagnostics- Selenite F Broth

10. Thank you