E. coli in Drinking Water
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Fungal Sampling Information
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Non-Fungal Sampling Information
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Qualtest, Inc. 2458 Alton Parkway Irvine, CA 92606 Phone: (949) 838-0378 Contact Us
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Introduction
Qualtest, Inc. offers the simultaneous detection and confirmation of total
coliforms and E. coli in water. Qualtest is capable of detecting Escherichia coli
in drinking water, ground water or surface water using Colilert®.
General Information
E. coli is a type of fecal coliform bacteria commonly found in the intestines of
animals and humans. E. coli is short for Escherichia coli.
Source of E. coli Contamination
The presence of E. coli in water is a strong indication of recent sewage or
animal waste contamination. Sewage may contain many types of disease-
causing organisms including E. coli.
Fecal Coliform Bacteria
Fecal coliforms are bacteria that are associated with human or animal wastes.
They usually live in human or animal intestinal tracts, and their presence in
drinking water is a strong indication of recent sewage or animal waste
contamination.
E. coli or Fecal Coliform Bacteria in the Water
E. coli comes from human and animal wastes. During rainfalls, snow melts, or
other types of precipitation, E. coli may be washed into creeks, rivers,
streams, lakes, or groundwater. When these waters are used as sources of
drinking water and the water is not treated or inadequately treated, E. coli
may end up in drinking water.
Spread of E. coli
E. coli from the stool of infected persons can be spread by contact or by
drinking sewage contaminated drinking water. This is the concern in flooded
areas. It can also be spread to others if hygiene is inadequate. Another source
of infection is from contaminated food, for example, from eating
contaminated meat from animals infected with pathogenic E. coli.
Health Effects of E. coli O157:H7
E. coli O157:H7 is one of hundreds of strains of E. coli. Most of the strains are
harmless and live in the intestines of healthy humans and animals. E. coli
O157:H7 strain produces a powerful toxin and can cause severe illness.
Infection often causes severe bloody diarrhea and abdominal cramps;
although sometimes the infection can cause non-bloody diarrhea.
People Who Are at Greater Risk
Children under the age of five, the elderly, and people whose health is
weakened (i.e., people who have long-term illnesses such as cancer or AIDS)
are at greater risk of severe illness.
The Safety of Your Drinking Water
Water Filters and E. coli
Most in-home filters will not be useful for E. coli elimination. The EPA recommends
that you boil your water if you are concerned about its safety.
Sample Collection Procedure
Water samples must be taken in approved, sterile sampling containers, which our
laboratory can provide upon request. Treated (municipality / distribution systems)
water samples must be de-chlorinated with sodium thio-sulfate (this is already in
bottles that would be provided by our laboratory). Keep the sampling bottle closed
until it is to be filled.
To test the content of your well or city water, flush the water for 5 to 10
minutes before collecting. Rinse the sample container several times with the
water to be tested, fill and close tightly.
To find out if pipes or filtering systems are contributing to poor water
quality, sample the water in the morning, before any flushing has been done.
Have a clean sample container ready, fill and close tightly.
Water must be collected in a sterilized container and brought to the Qualtest
laboratory for testing as soon as possible (within 6 hours after water has been
collected.)
100 mL is needed for each sample submitted for analysis.
If a sample is taken from a well fitted with a hand pump, pump water to
waste for about 5 minutes before collecting the sample. If the well is equipped
with a mechanical pump, collect sample from a tap on the discharge. If there
is no pumping machinery, collect sample directly from the well by means of a
sterilized bottle fitted with a weight at the base; take care to avoid
contaminating sample by any surface scum.
Summary of Method
This method is based on Defined Substrate Technology. It utilizes nutrient
indicators that produce color/florescence when metabolized by total
coliforms and E. coli. When the reagent is added to the sample and incubated,
it can detect these bacteria at 1 CFU/100mL within 18 to 24 hours.
Scope and Application
This method is intended for use in simultaneous detection and confirmation
of total coliforms and E. coli in water. Any positive sample for total coliforms
is an indication of contamination. Any positive sample for both total coliforms
and E. coli is an acute violation.
Colilert® method can be applied to fresh water, drinking water and waste
water. It is not intended for use with marine water.
Why using Colilert® Method
The test is an EPA approved method for determination of compliance with
requirements of the National Primary Drinking Water Regulations for Public
Water Supplies and the Surface Water Treatment Rule promulgated under the
Safe Drinking Water Act.
More that 90% of U.S. State labs use Colilert® method.
Identifies coliforms and E.coli simultaneously.
Detects a single viable coliform or E.coli per sample.
Detects total coliforms and E. coli in 24 hours or less.
Colilert-18® takes just 18 hours.
No confirmations needed.
Reporting Results
Report results as Presence or Absence for total coliforms and E. coli.
Chain of Custody
Must contain sampling date, time sampled, and sample source. This is needed
to determine whether or not samples are within hold times and analysis
procedure.
Transportation of Samples
All samples must be kept cold (not frozen) and should remain upright during
transportation. The best way to do this is to use ice packs. Samples that are
not transported properly could end up getting contaminated or rejected. All
samples must be analyzed within 6 hours of sample collection.
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