AOAC-RI ERP Book Micro Jan 19 2017

OMAMAN-35 B: Collaborative Study Protocol ERP USE ONLY January 2017

3M MDA2 E. coli O157:H7 Collaborative Study

May 2016

OMA-2016-May-XXXX

1 2 3 4 5 6 7 8 9

c) Study Schedule

a) All data should be sent to the SD by the 2 nd week of study.

b) The contract laboratory will prepare the test portions and ship the test portions refrigerated via overnight courier to the collaborators to arrive on a Friday. Test portion processing and analysis will begin on Monday. Data forms will be completed and faxed or emailed back to

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

the co-Study Director by the following Friday.

2) Test Portion Preparation

a) Fresh raw ground beef will be obtained from local retail outlets and screened for the presence of E. coli O157. Naturally contaminated test portions will be used if available at sufficient levels. Alternatively, the test portions will be artificially inoculated to meet the targets of 0.2-2.0 cfu/test portion for the low and 2 – 5 cfu/test portion for the high with the appropriate

concentration of a wet inoculum.

b) Preparation of test portions . A liquid inoculum will be added drop-wise to a bulk quantity of ground beef for each inoculation level - 0.2-2 cfu/25g and 2-5 cfu/25g. The bulk quantity will then be mixed to achieve equal distribution of analyte throughout. Test portions (25g) will be pulled from this bulk lot and randomly assigned to the reference method or the 3M MDA2 - E. coli O157 (including H7) method. An additional 300g uncontaminated raw ground beef will be added to the 25g test portion resulting in a 325g test portion. The test portions will be stored at c) 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. 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 d) Microbiological analysis. The test portion preparation is different for the 3M MDA2 - E. coli O157 and reference methods. Therefore, each collaborator will receive a separate test portion for each method. They will be instructed to test 325 g ground beef using the 3M MDA2 - E. coli O157 method and another 325 g ground beef using the MLG reference method. 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 flagellar (H) tests will also be 2-8  C for 72-96 h prior to testing. analyzed.

AOAC Research Institut Expert Review Panel Use Only

performed.

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.

DRAFT DOCUMENT

5