Cetrimide Broth

Media
Lauryl Sulfate or Lauryl Tryptose Broth
Products
Lauryl Sulfate or Lauryl Tryptose Broth
Used for the detection of coliform
organisms in water, wastewater and
foods.
Description:
This media was developed for the
detection of coliform organisms by the
American Public Health Association
(APHA). It is now the standard medium
of choice in the presumptive phase of
the standard coliform MPN test for the
microbiological examination of water.
Interpretation:
Lactose acts as a source of fermentable
carbohydrates for coliforms. The
fermentation of lactose with gas formation
is a presumptive test for coliforms.
Sodium lauryl sulfate inhibits the
growth of organisms other than coliforms.
Quality Control and recommended
incubation conditions:
Positive control:
Escherichia coli ATCC 29522
incubation for 24–48 hours at 35º C.
Negative control:
Enterococcus faecalis ATCC 19433
incubated at 35º C for 24–48 hours =
no growth.
Sterility test:
7 days plated sterility test.
Lauryl Sulfate Broth: Pure culture of Escherichia
coli ATCC 25922 cultivated on this media shows
normal growth with gas formation.
Formulation:
Per liter of water adjusted
to pH 6.8 ± 0.2
Sodium lauryl sulfate
Pancreatic Digest of Casein
Lactose
Dipotassium phosphate
Monopotassium phosphate
Sodium chloride
0.1 g
20.0 g
5.0 g
2.75 g
2.75 g
5.0 g
Organisms
Characteristics
E. coli ATCC 25922 Growth/gas
E. aerogenes ATCC 13048 Growth/gas
S. faecalis ATCC 29212 inhibited
Order information Lauryl Sulfate or Lauryl Tryptose Media
Product Description Qty/Pkg Order No
Lauryl Sulfate or Lauryl Tryptose Broth 9 ml vials 20 10 496 722
Petri dishes with sterile pads 47 mm 100 10 498 544
Petri dishes with sterile pads 50 mm 50 10 445 905
* available on request
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