ERP Micro December 2019

Analysis of discordant results

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For all categories evaluated, 34 negative deviations and 34 positive deviations were observed. Due to the 2 difference of sampling between both methods, and the use of naturally contaminated samples and inoculated 3 samples with low levels of contamination, Listeria may not have been present in the samples of the alternative 4 or reference method resulting in the positive or negative deviations. For four of the negative deviations, 5 positive results were obtained culturally with the alternative method. For these samples, it is probable that the 6 enrichment did not allow cells to reach the threshold of detection for the candidate method. Table 6 presents 7 an analysis of the discordant results. 8 Table 6 - Analysis of discordant results for the RLOD Study 9

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Conclusion: The observed values for ((ND + PPND) - PD) are below the acceptability limit for each

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category and for all the categories.

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40