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(Applicable to the detection of
Salmonella
in raw ground beef (25 g and 375 g), chicken carcass rinse,
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hot dogs, beef trim, ground beef with soy, ground turkey, cream cheese, fresh bagged lettuce, orange
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juice, frozen peas, peanut butter, shell eggs, shrimp, white pepper, ice cream, non-fat dry milk, dried
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eggs, cocoa, and infant formula, and dry pet food (375 g), and on stainless steel, ceramic tile, and plastic
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surfaces)
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Caution:
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Kits
— Reagents used in the BAX® System
should pose no hazards when used as directed. Dispose of
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lysate, PCR mixture and other waste according to your site practices.
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Cycler/detector
— Only qualified laboratory personnel should operate the cycler/detector. Do not
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attempt to repair the instrument. Live power may still be available inside the unit even when a fuse has
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blown or been removed. Refer to the BAX® System User Guide for maintenance procedures when
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cleaning the unit or changing a fuse. The heating block can become hot enough during normal operation
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to cause burns or cause liquids to boil. Wear safety glasses or other eye protection at all times during
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operation.
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Enrichment Broths
— All enrichment broths may contain varying pathogens whether they contain
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Salmonella
or not and thus should be sterilized and disposed of using proper procedures following
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any culture-based confirmatory steps.
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A.
Principle
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The BAX® System uses the Polymerase Chain Reaction (PCR) to amplify a specific fragment of
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bacterial DNA, which is stable and unaffected by growth environment. The BAX® System simplifies
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the PCR process by combining the requisite primers, polymerase and nucleotides into a stable, dry,
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manufactured tablet already packaged inside the PCR tubes. After amplification, these tubes
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remain sealed thus significantly reducing the potential for contamination with one or more
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molecules of amplified PCR product in future tests.
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This automated BAX® System method uses fluorescent detection to analyze PCR product. One
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PCR primer for each target (one
Salmonella-
specific target and an internal control) contains a
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fluorescent dye (two different dyes, one for each target) as a constituent of the primer as well as a
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quencher (the uni-molecular combination of a primer, fluorescent dye and quencher constitute a
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Scorpion™ Probe). When not incorporated into a PCR product, the Scorpion™ Probe has a hair-pin
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loop structure which keeps the dye and quencher in close proximity. When incorporated into a PCR
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product, the dye and quencher are spatially separated due to an internal hybridization, which
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causes an increase in emission signal. The BAX® System measures the magnitude and
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characteristics of fluorescent signal change. An analysis by the BAX® System software algorithm
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then evaluates that data to determine a positive or negative result.
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B.
Apparatus
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(a)
BAX® System Q7 cycler/detector with computer workstation.
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(b)
BAX® System application software.
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Collaborative Study Approved Protocol
Expert Review Panel Use Only