E.coli IDEXX Method

E.coli, also known as Escherichia coli, is a bacterium that is found in the intestines of warm blooded animals. E.coli is a good indicator of health risks in fresh water and is currently recommended for testing of E.coli instead of fecal coliform bacteria.

The State of Utah has a Standard Operating Procedure for collecting and handling of Escherichia coli (E. coli) samples. Below are simplified steps for collecting E. coli samples broken up by Reservoirs/Lakes and Rivers/Streams.

Reservoirs/Lakes Rivers/Streams

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Sampling at Reservoirs/Lakes

Steps

Illustration

  1. Check and record GPS coordinates of sampling site.
  1. Label 120 ml bottles with sampling location, replicate number, time, and date.
  1. Prepare the field blank using distilled/deionized water (one field blank per trip).
  1. Take a thermometer and the 3 120 ml sterile sampling bottles you labeled out into the reservoir until approximately knee deep.
  1. Record water temperature. For instructions on how take the water temperature click here.
  1. Gently invert and fill up the first replicate bottle at a depth of 12-18 inches. Make sure to fill the bottle to the 100 ml mark as accurately as possible.
  1. Replace lid securely and mix by shaking the bottle.
  1. Walk 10 feet in one direction, parallel to the shoreline to fill up the second replicate.
  1. Walk 10 more feet in the same direction, parallel to the shoreline, to fill up the third replicate.
  1. Store samples on wet ice or ice packs. Deliver samples to the laboratory within 8 hours for processing.

Sampling at Rivers/Streams

Steps

Illustration

  1. Check and record GPS coordinates of sampling site.
  1. Label 120 ml bottles with sampling location, replicate number, time, and date.
  1. Prepare the field blank using distilled/deionized water (one field blank per trip).
  1. Take a thermometer and the 3 120 ml sterile sampling bottles you labeled out into the thalweg (main flow).
  1. Record water temperature. For instructions on how take the water temperature click here.
  1. Gently invert and fill up the first replicate bottle just below the water surface. Make sure to fill the bottle to the 100 ml mark as accurately as possible.  Repeat with the next bottles.
  1. Replace lids securely and mix by shaking the bottles.
  1. Store samples on wet ice or ice packs. Deliver samples to the laboratory within 8 hours for processing.