Lauryl Sulfate Tryptose Broth

Usages?
Determination of coliform and faecal coliform for multiple tube fermentation.
 
Principle:
Tryptone provides carbon and nitrogen sources to meet the needs of bacterial growth; sodium chloride osmotic pressure balance can be maintained; Lactose is a coliform fermentable sugars; potassium dihydrogen phosphate and dipotassium phosphate is a buffer; lauryl sodium can inhibit the growth of non-coliform bacteria.
 
Formulation (per litre):
Trypticase:20g
Sodium chloride: 5g
Lactose:5g
Potassium dihydrogen phosphate: 2.75g
Dipotassium hydrogen phosphate: 2.75g
Sodium lauryl sulfate 0.1g
Final pH6.8 ± 0.2
 
How to use:

1. Suspend 35.6g of the product, adding 1 L of distilled or deionized water, heated to boiling stirring until completely dissolved, packed in a test tube with a small down tube, 121^oC autoclave 15min, leave to cool to room temperature, standby.
2. Sample handling and dilution.
3. Selected three consecutive dilutions, each dilution was inoculated three LST broth tubes, each tube was inoculated 1mL.
4. Put the tubes in an incubator 36 ± 1^oC cultured for 48 ± 2h.
5. Observe the results. if all LST broth doesn’t produce gas, can be reported as negative for E. coli, if gas production then will have to make further confirmed by experiments.

 
Quality control:
Quality control strains were inoculated and culture at 36 ± 1^oC for 24h, results are as follows:

Bacteria name	Growth situation	Gassing
Escherichia coli ATCC25922	Good	+
Salmonella typhimurium CMCC (B) 50115	Good	-
Staphylococcus aureus ATCC6538	Suppressed	-

 
 
Storage: Store in a dark, cool and dry place, tighten the cap immediately after use. Storage period of three years.