Microbiology Methods for ERP Review 3-2020

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GENE ‐ UP ® SLM 2 Collaborative Study

July 2019

b) Confirmation should be performed using the enrichment broth stored at 2–8°C and should be initiated within 72 h following the end of the incubation period. If using an enriched sample, mix thoroughly by hand. Note: For short protocols, the confirmation can be made at the end of the incubation time (8 h or 10 h). c) Isolate the enrichment broth on a SALSA™ agar plate, on CHROMID ® Salmonella, on ASAP™ or XLD agar plates; incubate at 35°C ± 1°C for 24 ± 3 h. d) If a typical colony is obtained, test an isolated colony directly using a Salmonella spp. latex or API® 20E strip. e) In the event of discordant results (positive with the alternative method, not confirmed by one of the options described above), the laboratory must take the necessary steps to ensure that the results obtained are accurate. It is recommended, for example, to perform the following procedure: (1) Transfer 100 μ L from the enrichment to 10 mL SX2 for a second enrichment. Incubate at 42°C ± 1°C for 24 ± 3 h. (2) Use a loop to isolate the sample directly from the second enrichment. (3) Streak the sample on SALSA™, CHROMID ® Salmonella, ASAP™, and/or XLD agar plates. (4) Incubate at 35°C ± 1°C for 24 ± 3 h. (5) Alternatively, VIDAS® SLM (or SPT) can be performed with an input volume of 500 μ L of SX2 broth. (6) If no typical Salmonella colony is identified, the result is considered negative. (7) If a typical colony is obtained, test an isolated colony directly using a Salmonella spp. latex or API® 20E strip.

6) Reporting Raw Data

a) Report data using the data report form in Appendix 8.2.

b) Upon completion the laboratory will fax or email the completed data form to the Study Director.

c) Copies of all related test results (data sheets and confirmation results) should be retained by the collaborators for a minimum of one year. 7) Analyzing Raw Data a) The resulting data will be analyzed by the probability of detection (POD) statistical model. a) Probability of Detection (POD)  ‐ POD is the proportion of positive analytical outcomes for a qualitative method for a given matrix at a given analyte level or concentration. POD is concentration dependent. Please see the revised microbiology guidelines for complete analysis information on POD calculations.

b) Calculate:

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