AOAC-RI ERP Book MICRO Sept 2016.pdf

OMAMAN-08/Collaborative Study Protocol March 2014 Expert Review Panel Use Only

3M Petrifilm SALX Collaborative Study

July 2013

OMA-2013-July-XXX

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the correct contamination levels are achieved. Test portions (25g) will be pulled from this bulk lot and randomly assigned to the reference method or the 3M SALX method. An additional 350g uncontaminated dry dog food will be added to the 25g test portion assigned to the 3M SALX method resulting in a 375g test

portion.

4.3 Shipment of test portions. Test portions will be packaged in leak-proof, insulated containers and shipped (according to the Dangerous Goods Regulations IATA for Infections Substances) by overnight carrier to arrive the day before initiation of analysis . All refrigerated test portions will be packed with ice packs to maintain a temperature of <7 ° C during transport. All dry test portions will be shipped at ambient temperature (22- 25°C). A temperature control sample will be included with each shipment to verify temperature of sample upon receipt. Upon arrival, the ground beef test portions will be stored at 2-8 ° C until they are analyzed and the dry dog food test portions will be stored 4.4 Microbiological analysis. The test portion preparation is different for the 3M Petrifilm SALX and reference methods. Therefore, each collaborator will receive a separate test portion for each method. They will be instructed to test 25g ground beef using the 3M Petrifilm SALX method and another 25g ground beef using the MLG reference method. They will be instructed to test 375g dry dog food using the 3M Petrifilm SALX method and 25g dry dog food using the BAM reference method. All test portions assayed by the 3M method will be confirmed following the reference method for confirmation of Salmonella species as described in the Alternative Confirmation section. The Reference Method Confirmation procedures will be performed starting with the secondary enrichment steps. The recovered isolates will be identified by the API20E (Official Method 978.24) or the VITEK2 GN (Official Method 2011.17). The somatic (O) and at room temperature until they are analyzed. One additional control (negative) test portion will be provided to each collaborator for each matrix to determine the total plate count on the day of analysis. 4.5 Most Probable Number (MPN) Analysis. To determine the level of Salmonella spp . in the inoculated food test portions on the day of initiation of analysis, a 5-tube MPN determination is performed by the coordinating laboratory following the appropriate reference method. From each of the inoculated food batches, prepare 5 test portions of 100 g, 5 test portions of 25 g and 5 test portions of 10 g. To each test portion, add BPW to make a 1:4 dilution. Follow the reference method through to confirmations. Use the number of positives from the high, medium and low levels to calculate the MPN for each flagellar (H) tests will also be performed.

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AOAC Research Institute Expert Review Panel Use Only

inoculated level of each matrix. Access the MPN calculator

( http://www.lcfltd.com/customer/LCFMPNCalculator.exe ) to determine the MPN values and 95% confidence intervals. Data should be entered from high level to low. Report

MPN as MPN/test portion.

5.0

3M™ Petrifilm™ Salmonella Express (SALX) System Method

Applicability

5.1

DRAFT DOCUMENT

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