1. Principle & application scope

E.coli O157:H7 can cause not only diarrhea and hemorrhagic enteritis, also, it is the cause for hemolytic-uremic syndrome and thrombotic thrombocytopenic purpura. E.coli O157:H7 has spread to many countries including America, Britain, Canada, and Japan since it is discovered in 1982. E.coli O157 count plate which adopted imported selective medium and specific enzyme chromogenic reagent is a kind of disposable rapid test product that can greatly simplify detection process.

Executive standard : Food sanitary microbiology test, Escherichia coliform O157:H7/NM test (GB/T4789.36)

2.  Using method

2.1 Sample preparation: Prepare the 1:10 solution by placing 25g or 25mL sample into 225mL sterilized saline.

2.2 Inoculation: Place the E.coli O157 count plate onto sterile experiment table, uncover the film on the surface. Suck 1mL solution with sterile pipette, and then drop it slowly and evenly onto the plate.Then cover the film gently and stand it for 10s to let the medium solidify. At last press it lightly by hand .Inoculate two count plates for each dilute ratio sample solution, and do a blank control test.  

2.3 Culture: Pile up the plates together and place them back to ziplock bags and seal them well. Place the count plates in the incubator with transparent side up. The quantity of superimposed count plates is no more than 12. The temperature of culture is 36℃±1℃, and the time of culture is 15-24h.

3. Results

E.coliO157:H7 would show purplish red while other coliform would show blue after the culture.The sample shows positive result should be veritified by other detection methods or take the sample to do at least one more test using E.coli O157 count plate.

4. Report

Detect whether there is Escherichia Coliform O157 for each 25g or 25mL sample.

5. Additional explanatory note

5.1 Culture medium that adopted in this product has been widely used abroad, and the accuracy of this product reaches 98%.（K.A. Bettelheim. 1998. J. Clin. Microbiol. 85:425-428）

5.2 Sensitivity of this product reaches 1CFU/mL.

5.3 Pay attention that count plates should be disposed timely according to biology safety waste treatment rule because there are live bacteria on them.