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SUBMITTED 050113, REVISED 102513
Use of the ANSR®
Salmonella
Test as a Confirmatory Procedure for Identification of
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Salmonella
spp. from Colony Picks from Selective/Differential Agar Media
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Maximilian Botimer, Carolyn Jagadics, Paul Norton, Mark Mozola
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, and Jennifer Rice
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Neogen Corporation, 620 Lesher Place, Lansing, MI 48912
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Corresponding author’s email:
mmozola@neogen.com7
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A single-laboratory pre-collaborative study was conducted to evaluate use of the ANSR® for
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Salmonella
test for identification of
Salmonella
spp. from colonies picked from agar media. Six
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selective/differential agar media commonly used in reference culture procedures for
Salmonella
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detection and identification were examined, along with non-selective tryptic soy agar. Of 791 tests
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conducted from 113
Salmonella
spp. strains, 784 tests produced positive results, for accuracy with
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inclusive strains of 99.1%. All negative results were obtained from one of two strains of the rare
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serovar
S
. Weslaco. Of 245 tests performed on 37 exclusive (non-salmonellae) strains, 242 produced
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negative results, for accuracy with exclusive strains of 98.8%. When the 3 isolates producing positive
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results were re-tested, all results were negative. It is concluded that the ANSR
Salmonella
assay can
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be used as a rapid, accurate tool for identification of presumptive
Salmonella
spp. isolates from agar
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media.
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Introduction
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The ANSR®
Salmonella
assay was originally developed as a screening test for food and environmental
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samples following broth culture enrichment. The method has been granted
Performance Tested
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Method
SM
(PTM) status by the AOAC Research Institute for testing of a wide variety of food and
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environmental samples (certificate no. 061203; [1, 2]). While useful as a screening method, the
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potential advantages of the assay as a confirmatory test for presumptive colonies taken from
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selective/differential agar plates are compelling. First, a presumptive colony can be definitively
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identified as
Salmonella
spp. in less than 40 min., compared with 6-24 h required by typical biochemical
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identification methods. Second, the method requires only minimal equipment and features an assay
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platform scaled for 1-16 determinations per experimental run.
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