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BAX® System PCR Assay

E. coli O157:H7 MP

When E. coli O157:H7 is present in a food sample, the genetic-based BAX® System uses the power of the polymerase chain reaction (PCR) with this multiplex assay to rapidly create (amplify) millions of copies of DNA fragments that are specific to E. coli O157:H7. This assay uses several additional markers on the E. coli O157:H7 genome for greater assurance that new, unusual or modified varieties of this complex organism are detected.

BAX® System assays simplify the method by combining all the PCR reagents you need into a single tablet, conveniently packaged inside the PCR tubes contained in each kit. Tableted reagents provide for minimal hands-on time, in addition to accuracy, long shelf life and consistency.

After standard enrichment, samples are lysed to break open the cell walls and release DNA. This lysate is then used to hydrate the PCR tablets. Processing in standard mode takes less than 4 hours for a full rack of 96 tests. Selecting the Express mode shortens processing time by about one hour. Electronic results appear as positive/negative icons on screen, and the data can be easily stored, shared or printed.


The BAX® System multiplex (MP) assay for E. coli O157:H7 detects both standard and unusual varietites of E. coli O157:H7 in beef and produce.

Validation studies have demonstrated that the BAX® System MP assay, after 8-24 hours enrichment in proprietary BAX® System MP media, performs significantly better than the USDA-FSIS culture method for detecting low levels of E. coli O157:H7 in raw ground beef. Performance between the methods was comparable for beef trim samples. Further, no significant performance difference was observed between the BAX® System MP standard and MP Express protocols.

With sensitivity/specificity rates of >99%, the BAX® Sytem for detecting E. coli O157:H7 MP assay has been adopted by the USDA-FSIS and certified by AOAC Research Institute as a Performance Tested method.

Recent outbreaks of E. coli O157:H7 in fresh produce are also driving new applications for this BAX® System assay. Studies on spinach and lettuce demonstrated excellent performance after 8-24 hours enrichment in BAX® System MP media. This enrichment protocol has also been validated by AOAC-RI for detecting Salmonella, so you can test for both targets from the same 8-hour enrichment.


USDA-FSIS MLG 5A.01 - raw ground beef and raw beef trim


Health Canada Supplement 2 to MFLP#30 - applies to dairy, meat, fruit and vegetables (after 18-24 hours in modified tryptic soy broth with novobiocin, mTSB-n) and to dry foods, environmentals and animal feed (after 1 hour in BPW, then 18-24 hours in mTSB-n). Also applies to ground beef and beef trim after 8-24 hours in BAX® System MP media.

AFNOR Certificate QUA-18/04 03-08 (Eng) (Fr) - raw beef in BAX® System MP media 8-24 hr; raw milk, fruits, vegetables and ready-to-eat meals, raw pork meat, raw horse meat and raw chicken meat in mTSB+novobiocin 18-24 hr - applies to  Q7 instruments

AOAC-RI Performance Tested Method 050501 - tested on raw ground beef, beef trim, spinach and lettuce.

  Samples of this test kit model were independently evaluated by the AOAC Research Institute and were found to perform tothe producer's specifications as stated in the test kit's descriptive insert. The producer certifies this kit conforms in all respects to the specifications originally evaluated by the AOAC Research Institute as detailed in the Performance Tested Certificate number 050501.

Ordering Info

P/N D12404903 -  BAX® System PCR Assay for Screening E. coli O157:H7 MP (96 tests per kit)

P/N D12404925 -  BAX® System MP Media (2.5 kg per tub)