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.

InoculumAmount of Medium in tube LactoseBroth used per 1L
1 ml10 ml or more13.0 g
10 ml20 ml19.5 g
10 ml10 ml26.0 g
100 ml20 ml78.0 g
100 ml50 ml39.0 g

 

Quality specifications:

Dehydrated medium: homogeneous, light beige fine powder.

Ready to use medium: light yellow and clear broth.

 

Microbiological response:

OrganismResult / gas production
Proteus mirabilis ATCC 12453Growth / –
Salmonella typhimurium ATCC 14028Growth / –
Pseudomas aeruginosa ATCC 27853Growth / –
Enterococcus faecalis ATCC 29212Growth / –
Enterobacter aerogenes ATCC 13048Growth / +
Escherichia coli ATCC 25922Growth / +

 

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.