LaMotte EZ 3-0034 - Manual (Page 8)

In ter pre ta tion of Re sults
• Non-fecal coliforms are widely distributed in nature, being found both as
naturally occurring soil organisms, and in the intestines of warm-blooded
animals and humans. Fecal coliforms, such as E. coli, are coliforms found
naturally only in the intestines of warm-blooded animals and humans. The
presence of fecal coliforms is therefore the result of some form of fecal
contamination from either animal or human.
• Be aware of animals, like ducks or geese, which may be upstream from where
the sample was taken because their feces will increase the E. coli and coliform
count temporarily, therefore, the results will not reflect the true nature of the
water quality.
• Proper application of the Coliscan Easygel method will result in accurate
results. Therefore, if the results indicate dangerously contaminated water,
contact your local health department for help in performing an official
assessment of the water quality.
• Water containing E. coli should not be used for drinking water. Contact your
local health department for guidelines regarding E. coli and coliforms in
recreational water.
• Most standard counts are reported as CFU/100mL of water
• Check your state water quality guidelines (see references).
Petri Dishes (Pretreated)
• Petri dishes supplied with this kit are coated inside with a special film. If storage
conditions vary, the film may develop a crystal pattern (too dry) or moisture
droplets may form or the film may become hazy (too moist). The dishes can be
used if these conditions exist.
• Coliscan Easygel WILL NOT work with Petri dishes that have not been
pretreated.
• Poured plates will solidify in about 45 minutes. Plates that will be streaked or
swabbed can be poured a day ahead.
• Petri dishes are intended for one time use only.
• Dispose of poured dishes in one of the recommended methods.
Sample Size and Ideal Colony Counts
• A smaller sample size should be used for samples with large coliform
concentrations to bring the number of colonies into a practical range. The
target range should be between 20 and 300 colonies. Below 20 colonies the
results will not be significant. Colonies greater than 300 will be too numerous
to count (TNTC).
• For samples with unknown levels of coliform, begin with a 1 mL sample size. If
counts are less than 20, then try a 5 mL sample size.
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