AOAC-RI ERP Micro June 2016

OMAMAN-29 D/ PTM Validation Report 111501 OMA ERP - June 2016 ERP Use Only

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Independent Laboratory Observations

The results of this study demonstrate the ability of the MDA 2 - Listeria to detect the presence of Listeria in various food matrixes and select environmental surfaces after 24-28 hours of a primary enrichment. The MDA 2 - Listeria offers the benefits of extremely high sensitivity and high specificity for the detection of Listeria while reducing the overall time to presumptive results. The MDA 2 - Listeria also reduces the total analyst time required to obtain final results by implementing a single heat lysis step and cool step, followed up by a single transfer to molecular reaction tubes. The small footprint of the Molecular Detection System requires only minimal lab and bench space, making it easy to move the instrument or pair up additional MDS units to perform multiple MDA runs concurrently. The updated software is user friendly with easy to interpret results. The ability to examine Relative Light Unit (RLU) curves makes trouble shooting more streamlined if any problems occur while testing is being conducted.

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Discussion

All matrixes evaluated in this validation study, including the raw chicken, resulted in no statistical differences when compared to the reference methods. Three different brands of Demi

Fraser with FAC were used in this study, referred to as X, Y, and Z.

There were no differences between the 24 and 26 hour primary enrichment time points for the environmental surfaces tested, therefore a 24 hour minimum enrichment time will be recommended for these matrixes: stainless steel, sealed concrete and plastic. The five false negative results with raw chicken (leg pieces) evaluated in the internal study resulted in an investigation of protocol. It was determined that the contract laboratory conducting the study used Demi Fraser with FAC brand X, which demonstrated low productivity. Brand X had also been used to analyze the inclusive list, spinach, and cold smoked When the protocol for raw chicken was performed at the independent laboratory, using a different brand Y, two lots of naturally contaminated raw chicken (leg pieces) analyzed showed no statistical difference when compared to the reference method. Lot 1 of the naturally contaminated raw chicken (leg pieces) had zero false negatives, while Lot 2 had two false To expand the robustness of the method to include multiple raw chicken matrixes, raw chicken fillets were chosen and brand Z was used. The raw chicken (fillet) testing resulted in no statistical difference when compared to the reference method, which highlighted the importance of internally validating any method as a system within one’s own laboratory. This is why 3M salmon. negatives.

AOAC Research Institute Expert Review Panel Use Only

has always emphasized this advisory within our package inserts;

“ As with all test methods, the source, formulation and quality of enrichment medium can influence the results. Factors such as sampling methods, testing protocols, sample preparation, handling, and laboratory technique may also influence results. 3M