LaMotte MF 3-0035 - Manual (Page 2)

• Wash hands thoroughly after performing tests. Avoid placing hands in contact
with eyes or mouth. Do not eat, drink, or apply cosmetics during testing or
clean up.
• Follow the general safety guidelines for your organization.
• Dispose of used dishes in the proper manner.
• Wipe tabletops and work areas after each use with disinfectant, such as a 1:10
dilution of household bleach.
• Testing by students: Ensure a safe field-testing experience by using the
following: safety glasses for each student, clean pail or bucket for washing
hands, jug of clean water for washing hands, soap (biodegradable if possible),
towels, protective gloves, eye wash bottle, first aid kit.
• Keep used Petri dishes taped shut and out of the reach of small children and
animals.
• Be sure that students understand the danger of treating reagents casually or
endangering others through “horseplay”.
ColiQuant MF Method
Coliscan MF (membrane filter) medium is a nutrient liquid formulation which uses two
color producing chemicals, one for the detection of the enzyme glucuronidase
(produced by E. coli strains but not by general coliforms) and one for the detection of
galactosidase (produced by all coliforms, including E. coli). A liquid sample
containing E. coli and other coliforms is passed through a membrane filter to leave
individual bacteria cells on the membrane filter. The filter is then placed on a pad
soaked with the Coliscan MF medium. When incubated at a suitable temperature, the
cells will grow into colony forming units (CFU) on the surface of the filter. If coliform
(including E. coli) colonies are present, they will produce the enzyme galactosidase,
which will react with its specific color producing substrate in the medium and a water
insoluble pink pigment will color the colony. If E. coli colonies are present, they will
also produce the enzyme glucuronidase, which will react with its specific color
producing substrate in the medium and a water insoluble teal-green pigment will
color the colony. However, since E. coli produces both galactosidase and
glucuronidase, those colonies will be a combination of teal-green and pink pigments
and will appear as some shade of blue-purple. 3
Col lecting a Wa ter Sam ple
1. Remove the cap of the collection bottle. Do not touch the neck of the bottle or the
inside of the cap.
2. If you are testing stream water, face upstream while holding the bottle 5 to 6
inches below the surface.
3. When the bottle has filled, replace the cap.
4. The test can be done at the site or water samples may be collected in sterile
collection containers and transported back to the testing site. Water samples kept
for more than one hour before testing should be kept on ice or refrigerated.
5. Do not reuse the sample collection bottle without sterilizing.
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