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KOOL
KOUNT Assayer (KKA) - KKA uses the biological reduction of
2,3,5 Triphenyl tetrazolium chloride (TTC) by actively metabolizing
microorganisms as its method. TTC is a redox indicator. The indicator
TTC is typically used as a color indicator with TSB media, standard
heterotrophic agar plates and dip slides. TTC is commonly referenced
in various general laboratory procedures for total viable microbe
measurements. In KKA, the rate of this indicator's reduction by microbes
over time is used to measure microbial concentration. In 1996, this
method was granted a patent, 5550032. This technique was submitted
for ASTM method approval in 1995 after completing the ASTM required
round robin evaluations for field test methods. In January 1998, the
method was approved by ASTM subcommittee D19.24 EC
KOUNT Assayer (ECKA) - ECKA uses the enzymatic hydrolysis
of MUG indicator reagent as its method. The MUG reagent is used in
both USEPA and AOAC approved methods as an indicator of E. coli presence.
The use of this reagent is described in several of the various E.
coli measurement techniques listed in section 9 of the 18th edition
of Standard Methods. The ECKA uses the technique of measuring the
rate of indicator hydrolysis over time as a measurement of E. coli
concentration. This method of MUG reagent use has been evaluated and
found to be better than 98% comparable to standard plate counts. The
results of this George Mason University (GMU) study are summarized
by the E.coli correlation curves for visual and spectrophotometric
analysis on attachment A. The calibration lines were determined by
over 100 data observations and application of Least Square Regression
Analysis. The data points represented on the graph are a statistical
sampling of these observations. For microbiological assays, the 99%
visual correlation and 98% spectrophotometric correlations are generally
considered excellent.. Additionally, MUG reagent based products (ie:
Colilert) have been compared favorably with MPN methods for E. coli
determinations. The results of the GMU study are the basis for a January
1998 patent application. This product will be review for AOAC approval
under its "Performance Tested Methodssm" program.
The study will commence in late February 1999. CF
KOUNT Assayer (CFKA) - Enzymatic hydrolysis of ONPG indicator
reagent. The ONPG reagent is used in both USEPA and AOAC approved
methods as an indicator of Coliforms presence. The use of this reagent
is described in several of the various Coliforms measurement techniques
listed in section 9 of the 18th edition of Standard Methods. The CFKA
uses the technique of measuring the rate of indicator hydrolysis over
time as a measurement of Coliforms concentration. This method of ONPG
reagent use has been evaluated and found to be 97% comparable to standard
plate counts. The results of this George Mason University (GMU) study
are summarized by the Coliforms correlation curves for visual and
spectrophotometric analysis on attachment B. The calibration lines
were determined by over 100 data observations and application of Least
Square Regression Analysis. The data points represented on the graph
are a statistical sampling of these observations. For microbiological
assays, the 97% visual correlation and 93% spectrophotometric correlations
are generally considered excellent. Additionally, ONPG reagent based
products (ie: Colilert) have been compared favorably with MPN methods
for Coliform determinations. The results of the GMU study are the
basis for a January 1998 patent application. This product will be
review for AOAC approval under its "Performance Tested Methodssm"
program. The study will commence in late February 1999. |
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