AOAC ERP MICRO AUGUST 2018

OMAMAN-44 A: Collaborative Study Manuscript Expert Review Panel Use Only August 2018

colonies using confirmation methods. Twelve to twenty five samples are compared at neat, 10 -1 and 10 2 528

dilutions to achieve a countable range 1–154 CFU/mL. Results are compared to reference methods using 529

a statistical population analysis. Peel Plate EB population results should be within 0.2 log mean 530

531

difference with population confidence interval greater than P>0.01.

532

Accelerated stress testing is performed 45 days at 37°C to assure 18 month refrigerated shelf life

and 1 year 0-25°C. Recovery experiments comparing n=10 test pairs of various Enterobacteriaceae 533

strains are performed to verify no significant difference P>0.05 from prior production and reference 534

methods. A non-coliform strain, Lactobacillus , is also evaluated to make sure there is no degradation of 535

selection agents in the stressed tests. Real time storage testing are also performed to verify 536

537

performance at shelf date.

538

Additionally, production quality control specifications for the dryness of the plates, <4.5%, are

reviewed and additional testing added if manufactured products exceed those specifications. 539

540

A summary of these evaluations for several lots of manufactured product are supplied in Table 10.

These testing parameters are designed to assure the product consistency and stability until its 1 year 0- 541

542

25°C shelf life.

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Robustness Studies

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Robustness studies were performed using perturbations of the critical steps of the Peel Plate EB ERP Use Only incubation, low 35°C and high 39°C, and time of incubation, low 22 h and high 26 h and 46 h and 48 h. 548 The assays were performed in buffer with two ATCC strains, with 10 replicate tests under each assay 549 546 method (14). The steps and perturbations evaluated were pipetting, 1.0 mL ± 0.1mL, temperature of 547

condition. Each perturbation condition was compared to the control condition in a paired t-test analysis. 550

551

Results of the robustness analysis are reported in Table 11.

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