Description
Use and description:
Pre-enrichment broth for Salmonella species, recommended by U.S.P. in the presumptive test of coliform organisms. Lactose fermentation is shown by gas formation in Durham fermentation tubes.
Composition per litre:
Lactose………………………………………..…5.0 g
Meat extract………………………….………3.0 g
Peptone…………………………………………5.0 g
Final pH of the ready to use medium: 6.9 ± 0.2
Medium preparation:
Add 13.0 grams of dehydrated culture medium to 1 litre of distilled water. Mix thoroughly. Distribute into tubes containing an inverted Durham tube and autoclave for 15 min at 121°C.
| Inoculum | Amount of Medium in tube Lactose | Broth used per 1L |
| 1 ml | 10 ml or more | 13.0 g |
| 10 ml | 20 ml | 19.5 g |
| 10 ml | 10 ml | 26.0 g |
| 100 ml | 20 ml | 78.0 g |
| 100 ml | 50 ml | 39.0 g |
Quality specifications:
Dehydrated medium: homogeneous, light beige fine powder.
Ready to use medium: light yellow and clear broth.
Microbiological response:
| Organism | Result / gas production |
| Proteus mirabilis ATCC 12453 | Growth / – |
| Salmonella typhimurium ATCC 14028 | Growth / – |
| Pseudomas aeruginosa ATCC 27853 | Growth / – |
| Enterococcus faecalis ATCC 29212 | Growth / – |
| Enterobacter aerogenes ATCC 13048 | Growth / + |
| Escherichia coli ATCC 25922 | Growth / + |
Storage:
Dehydrated medium should be stored between 10 to 25°C. Once opened, place the container in a dark, dry place. The dehydrated medium should not be used if there is any lump or the colour has changed from the original.