Himedia Lactose Broth 500 gr cat. M1003-500G
Lactose Broth M1003
Recommended for the detection of coliform bacteria in water, foods, dairy products and clinical samples.
Ingredients Gms / Litre
HM Peptone B# 3.000
Final pH ( at 25°C) 6.9±0.2
**Formula adjusted, standardized to suit performance parameters
Suspend 13.0 grams in 1000 ml purified/ distilled water. Heat if necessary to dissolve the medium completely. For larger
inocula (10 ml or more), concentrated medium may be prepared to account for medium dilution by the inoculum.
Dispense in tubes containing inverted fermentation vial (Durhams tube) as desired. Sterilize by autoclaving at 15 lbs
pressure (121°C) for 15 minutes.
Principle And Interpretation
Examination of water, foods, ingredients and raw materials, for the presence of marker groups such as coliforms is one of the
most common tests in a microbiology laboratory, partly because of the relative ease and speed with which these tests can be
accomplished. Where it is claimed that drinking water has been processed for safety, the finding of such organism
demonstrates a failure of the process. It is a valuable bacterial indicator for determining the extent of fecal contamination of
recreational surface waters or drinking water
(1). Lactose Broth is recommended by APHA in the performance and confirmation of the presumptive test for coliform bacteria
in water (2), food (3) and milk (4). This medium was initially listed as an alternative to Lauryl Sulfate Broth in the
presumptive Standard Total Coliform Multiple-Tube (MPN) Test for water analysis. Although it is not the original
formulation, Lactose Broth provides excellent results in Eijkman Assays of gas production at 45°C, which is a characteristic
of Escherichia coli . While preparing this medium it is important to avoid overheating and to distribute it into tubes before
Principle And Interpretation
Peptone and HM Peptone B in the medium supply nitrogenous and carbonaceous compounds, long chain amino acids
and other essential nutrients to the organisms. Lactose is a fermentable carbohydrate for the coliforms. Tubes of Lactose
Broth are inoculated with ddilutions of water or milk, etc. under test, and incubated at 35°C and examined for gas formation
after 24 and 48 hours. Members of the coliform group are defined as aerobic and facultative anaerobic gram-negative
and non-sporing bacilli, which ferment lactose with gas formation within 48 hours at 35°C. In testing dairy products,
Lactose Broth is used only in the completed test (3). Large water samples may require double strength Lactose Broth to
minimize the final volume.
# – Equivalent to Beef extract
Clinical samples – urine, body fluids, Food and dairy samples ; Water samples
Specimen Collection and Handling:
A For clinical samples follow appropriate techniques for handling specimens as per established guidelines (5,6).
For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (3,4).
For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards.(2)
After use, contaminated materials must be sterilized by autoclaving before ddiscarding.