ERP Micro December 2019

(e) Check that the results obtained correspond to the characteristics of the tested strains.

K. Limitations of the Method

The GENE‑UP ® Listeria monocytogenes 2 (LMO 2) kit has been evaluated on a large number of matrices. However, given the wide variety of products and manufacturing procedures, it is recommended to check that the composition of the matrices tested does not affect the reliability of GENE‑UP ® results.

Results of Collaborative Study

The collaborative study involved a method comparison evaluation of the candidate method to the ISO 11290-1/Amd.1 reference method for full-cream goat milk cheese (8.4% fat). A total of 16 participants from 15 laboratories throughout the European Union participated in this study. Each participant analyzed 24 unpaired test portions for the candidate method and the ISO reference method: eight inoculated with a high level of L. monocytogenes, eight inoculated with a low level of L. monocytogenes , and eight non-inoculated controls. One collaborator (11) received damaged samples and was not able to participate. All other collaborators submitted data which were included in the statistical analysis. Table 2019.1A summarize the results of the collaborative study. Detailed results for each laboratory are presented in Table 2019.2A. The level of L. monocytogenes , and 95% confidence interval, was determined on the day of initiation of analysis by the coordinating laboratory: 1.9 CFU/test portion (1.5, 2.4) for the low inoculum level and 9.2 CFU/test portion (7.2, 11.4) for the high inoculum level. The individual collaborator sample results are presented in Table 1 of the Supplementary Materials. The results of the APC analysis produced a range of 6.6 x 10 2 and 4.7 x 10 8 CFU/g. Two participants, from the same laboratory, reported APC counts at 6.6 x 10 2

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