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808 Bird et al.: Journal of AOAC International Vol. 96, No. 4, 2013
Evaluation of VIDAS® UP Salmonella (SPT) Assay for
the Detection of Salmonella in a Variety of Foods and
Environmental Samples: Collaborative Study
Patrick Bird , Kiel Fisher, Megan Boyle, Travis Huffman , Marc Juenger, M. Joseph Benzinger, Jr,
Paige Bedinghaus, J onathan Flannery, E rin Crowley, James Agin, and David Goins
Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214
Ronald L. Johnson1
BioMérieux, Inc., 595 Anglum Rd, Hazelwood, MO 63042
Collaborators: M. Achen; J. Adams; M. Bandu; J. Clayborn; L. Drasher; H. Elgaali; W. Fedio; K. Goetz; Y. Huang; J. Jurgens;
H. Kohler; D. Kondratko; S. Liles; T. Lonczynski; K. McCallum; J. Mills; S. Montez; J. Nogle; M. Oltman; J. Pickett; J. Rowe;
L. Thompson; J. Walia; R. Zapata
Submitted for publication February 2013.
The recommendation was approved by the Methods Committee on
Microbiology as First Action.
1Corresponding author’s e-mail:
Appendixes are available on the J. AOAC Int. website,
DOI: 10.5740/jaoacint.CS2013_01
MICROBIOLOGICAL METHODS
The VIDAS® UP Salmonella (SPT) uses recombinant
phage proteins to detect Salmonella species in
human and animal food products and production
environmental samples after 18–26 h of enrichment.
The VIDAS SPT assay is performed with the
automated VIDAS or mini-VIDAS instruments.
The VIDAS SPT method was compared in a
multilaboratory collaborative study to the U.S.
Department of Agriculture/Food Safety and
Inspection Service-Microbiology Laboratory
Guidebook (USDA/FSIS-MLG) 4.05 (2011) Isolation
and Identification of Salmonella from Meat, Poultry,
Pasteurized Egg and Catfish Products reference
method following the current AOAC guidelines. A
total of 15 laboratories representing government,
academia, and industry throughout the United
States participated. One matrix, raw ground beef,
was analyzed using two different test portion sizes,
25 and 375 g. Each test portion was artificially
contaminated with Salmonella at three inoculation
levels, an uninoculated control level (0 CFU/test
portion), a low inoculum level (0.2–2 CFU/test portion),
and a high inoculum level (2–5 CFU/test portion).
In this study, 1656 unpaired replicate samples were
analyzed. Of those unpaired replicates, 476 were
presumptive positive by the VIDAS method, with 475
confirmed positive by the traditional confirmation
procedures and 476 confirmed positive by an
alternative confirmation procedure. There were 411
confirmed positive replicates by the USDA/FSIS-MLG
reference method. Statistical analysis was conducted
according to the probability of detection (POD).
For the low-level 375 g test portions, the following
dLPOD values, with 95% confidence intervals, were
obtained: 0.01 (–0.12, +0.15) for samples confirmed
following the traditional confirmation; 0.02 (–0.18,
+0.2) for samples confirmed following traditional
confirmation on IBISA and ASAP; and 0.03 (–0.18,
+0.24) for samples confirmed following the alternative
confirmation on IBISA and ASAP. For the low-level
25 g test portions, the following dLPOD values,
with 95% confidence intervals, were obtained: 0.41,
(0.32, +0.49) for samples confirmed following the
traditional confirmation, the traditional confirmation
on IBISA and ASAP, and the alternative confirmation
on IBISA and ASAP. With 0.0 within the confidence
intervals for the 375 g test portions, there was no
statistically significant difference in the number
of positive samples detected by the VIDAS SPT
method and the USDA/FSIS-MLG method at the
0.05 level. For the 25 g test portions, a statistically
significant difference was observed between the
VIDAS SPT method and the reference method for the
low inoculum level, where the VIDAS SPT method
recovered a higher number of positive results than
the reference method. It is recommended that the
VIDAS SPT method with the optional ASAP and IBISA
agar confirmation method be adopted for Official
First Action status for the detection of Salmonella
in a variety of foods and environmental samples.
Salmonellosis, the foodborne illness caused by the
bacterium Salmonella, has been linked to numerous
foodborne outbreaks associated with a wide range of
products, such as meat, poultry, eggs, dairy products, fresh
produce, spices, sauces, peanut butter, and chocolate (1). Taking
up to 5 days to confirm, the detection of Salmonella species can
be time-consuming and expensive for food manufacturers. With
more than 2500 different serovars, Salmonella are antigenically
complex due to variations in their lipopolysaccharide and
flagellar protein antigens (1). The VIDAS UP Salmonella (SPT)
assay, an automated enzyme phage-ligand-based assay for the
detection of Salmonella in food and environmental samples,
uses recombinant phage proteins to detect both motile and
Candidates for 2016 Method of the Year
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