Sample: water/sludge collected in a sterile container (for chlorinated water use a container with sodium thiosulfate neutralizer); swab of solid surface; bulk sample submitted in sterile container.
Method:
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- Quantitative or qualitative selective culture for E. coli, fecal coliforms, and Enterococcus (fecal streptococci); quantitative cultures will be reported as colony forming units (CFU) per unit area (swabs); CFU/mL (water); or CFU/g (bulk).
- 24-hour sewage screen (water, swabs) – presence/absence of E. coli, fecal coliforms, and Enterococcus (fecal streptococci).
Collection: Sterile screw-top containers and swabs are available free of charge from U. S. Micro-Solutions, call 724-853-4047. Do not use “Q-tips” or other cotton swabs intended for personal use; they are not appropriate for environmental sampling.
Swabs
- Select a sampling area where fecal contamination is suspected.
- An area between 1 and 4 square inches is recommended for swab cultures.
- For 24-hour sewage screen, collect 2 swabs.
- Wearing gloves, peel down the swab wrapper about 1 inch.
- Apply strict aseptic technique when collecting samples.
- Remove the plug from the media tube by twisting; discard the plug.
- Remove the swab from the wrapper and insert it into the media tube.
- Squeeze the bottom of the tube until the liquid in the sponge wets the swab.
- Rub the pre-moistened swab vigorously over the desired sampling area.
- Insert the swab into the media tube and firmly close the cap.
- Record the sample number on the tube.
- Record the unit area sampled for each swab.
- Maintain sample at 2-8°C after collection.
Water
Potable Water – Distribution System without attachments:
- Select a tap that is supplying water from a service pipe directly connected with the main, and is not, for example, served from a cistern or storage tank.
- Open tap fully and let water run for 2 minutes or for a time sufficient to permit clearing of the service line.
- Reduce water flow to permit filling the sample container without splashing. Collect 100 mL of water.
- For 24-hour sewage screen, collect 200 mL
- Label the sample container with the sample number.
- Maintain sample at 2-8°C after collection.
Potable Water -Well fitted with a hand pump:
- Pump water for about 5-10 minutes or until water temperature has stabilized then fill the sample container without splashing. Collect 100 mL of water.
- For 24-hour sewage screen, collect 200 mL
- If no pumping machinery is available, collect a sample directly from the well by means of a sterilized bottle fitted with a weight at the base. Take care to avoid contaminating samples. Collect 100 mL of water.
- For 24-hour sewage screen, collect 200 mL
- Label the sample container with the sample number.
- Maintain sample at 2-8°C after collection.
Shipping:
- Clearly label each sample with a Sample Number and complete the Chain of Custody (COC).
- Place sample in a Ziploc bag and then in a box with an insulated foam liner and ice pack.
- Insert the completed COC form into a plastic sleeve or Ziploc bag and place in box.
- Ship samples Monday through Friday for receipt within 24 hours of collection.