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All samples were confirmed according to the appropriate reference methods specified for
the matrix and analyte:
(a)
USDA/FSIS-MLG 5.09: Detection, Isolation and Identification of
Escherichia coli
O157:H7 from Meat Products and Carcass and Environmental Sponges
(b)
USDA/FSIS-MLG 5B.05: Detection and Isolation of non-O157 Shiga Toxin-
Producing
Escherichia coli
(STEC) from Meat Products and Carcass and
Environmental Sponges
(c)
FDA/BAM Chapter 4A: Diarrheagenic
Escherichia coli
Independent Validation Study
In accordance with an AOAC-RI Performance Tested Method program approved study
design, the method developer study was conducted by an Independent laboratory, Q
Laboratories, Inc., in Cincinnati, Ohio.
The study was conducted according to the procedures outlined in the AOAC Research
Institute Performance Tested Methods
SM
protocol:
Independent Laboratory Study for the
mericon
E. coli
O157 Screen Plus and mericon
E. coli
STEC O-Type
Pathogen Detection
Assay
(February 2015, Version 1) [7]
.
The
mericon
E. coli
O157 Screen Plus
and
mericon
E.
coli
STEC O-Type
Pathogen Detection Assay
were compared to the following reference
methods: FDA/BAM Chapter 4A for fresh spinach,USDA/FSIS-MLG 5.09 for raw ground
beef (70% lean), and to the USDA/FSIS-MLG 5B.05 for fresh raw beef trim. The study
outline consisted of inclusivity, exclusivity, method comparison, and robustness
evaluations. The inclusivity, exclusivity and robustness evaluations were conducted using
the manual
mericon
DNA extraction procedure. The method comparison study used both
the manual and automated
QIAsymphony
DNA extraction procedures. All data were
analyzed using the Rotor-Gene Q series software.
Inclusivity and Exclusivity
For the inclusivity evaluation of the
mericon
E.coli O157Screen Plus and
mericon
E.coliSTEC O-Type
Pathogen Detection Assay
, 50 pathogenic
E.coli
strains
(including the serovars: O157, O26, O45, O103, O111, and O145)were cultured in mTSB +
CAA for 8-10 hours at 42 ± 1°C and then diluted to 100x the Limit of Detection (LOD =1 x
10
3
).
For the exclusivity portion of the validation, 30 species/strains (including non-pathogenic
E.coli
and non-regulated STEC serovars) closely related to STECs were grown in Brain
Heart Infusion (BHI) broth for 22 ± 2 hours at 37 ± 2ºC.
Inclusivity and exclusivity cultures were randomized, blind-coded and then analyzed with
the appropriate
mericon
assay using the manual
mericon
DNA extraction procedure.
Matrix Study
OMAMAN-36 E/ AOAC PTM Report
ERP Use Only
January 2017
AOAC Research Institute
Expert Review Panel Use Only