Selenite mannitol broth is a modification of selenite broth and is for the selective enrichment of Salmonellae spp. from clinical, food and environmental specimens. Comparisons have shown that mannitol selenite broth is better than other enrichment broths for the isolation of Salmonellae spp.
The peptone acts as a nitrogen, carbon and vitamin source. Mannitol is a fermentable carbohydrate and sodium phosphate is a buffer. The medium is made selective by the addition of sodium biselenite (KM8021). The fermentation of mannitol by Salmonellae spp. is said to correct the alkaline pH swing which can occur during incubation.
Following overnight incubation subculture(s) are usually made on to one or more of the many selective enteric solid media.
KM0022 – Selenite Mannitol Broth Base
Additional Information
| Shelf Life (days) | |
|---|---|
| Storage Temp (°C) | |
| Dehydrated Medium Appearance | |
| Prepared Medium Appearance | |
| Dehydrated Medium Colour | |
| Prepared Medium Colour | |
| Dehydrated PH | |
| Prepared PH | |
| Recommended Incubation |
Product Description
| Organisms | Ref. No | Result |
| Salmonella typhimurium | NCTC 12023 | Growth |
| Escherichia coli | NCTC 12241 | Inhibited |
Formula*
| g/L | |
| Peptone | 5.0 |
| Mannitol | 4.0 |
| Sodium phosphate | 10.0 |
| Total | 19.0 |
| *Adjusted/supplemented as required to meet performance requirements |
Preparation
Suspend 19 g of the medium in one litre of deionised / purified water. Add 4 g of sodium bi-selenite (KM8021). Allow the medium to soak whilst mixing for 10 minutes. Heat with frequent agitation until boiling. Cool to 45-50°C, mix well and aseptically dispense into appropriate sterile containers.
To minimise any possible risk of teratogenicity to laboratory workers, the sodium biselenite must be added to this medium separately.
