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Wastewater Microbiology Samples
For Proficiency Testing
Quantitative: WP Total Coliform - Total Fecal
The lyophilization process generates a more stable bacteria sample. Liophilization
involves culturing and harvesting the bacteria, re-suspending the organisms
in a suitable freeze-drying medium, freezing the bacteria and finally
freeze-drying. Microorganisms prepared in this manner are stable for
prolonged periods of time. The reconstitution of the lyophilized
samples does require vigorous shaking to dissolve the coating material;
however, some cloudiness may still remain. The samples work very well
with the Standard Methods for the Examination of Water and Wastewater,
20th Edition, Method 9223 type of presence/absence analysis.
2005 WP Micro samples are available in the months of February, April, July, and October.
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Drinking Water Microbiology Samples
For Proficiency Testing
Qualitative: Presence / Absence
Analysis of total and fecal coliforms by the presence-absence concept as required
by the total Coliform Rule (40 CFR Parts 141 and 142). Each kit consists of 10
freeze-dried samples in aseptically sealed vials. Each vial contains either
Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, or a sterile blank.
Laboratories are to designate the contents of each vial as to the presence or
absence of total coliform bacteria and fecal coliform bacteria based on
accepted microbial methods. Methods used by laboratories are comprised of
Membrane Filtration, Multiple Tube Fermentation, MPN, Presence/Absence and
Chromogenic/Fluorogenic methods.
Quantitative: Heterotrophic Plate Count
This sample is used for estimating the number of live heterotrophic
bacteria in water. The sample for Standard Plate Count consists of
one freeze-dried sample in an aseptically sealed vial and is designed
for the quantitative determination of heterotrophic bacteria in the
range 5 to 500 cfu/mL. One hundred milliliters of Phosphate buffer
solution and sterile pipettes are provided for reconstitution of the
freeze-dried sample. The standard is designed to be used with Standard Method 9215B-Pour Plate Method.
2005 WS Micro samples are available with each bi-monthly PT study.
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