AOAC-RI ERP Book - Gluten.pdf

4. Procedure of the microbial testing

The microbial enrichment media CASO-Bouillon (TSB) EP + USP (catalogue number 1.46458.0010 / 146458) from Merck Millipore, Germany was used for detection of microbial contamination. All used wash buffers were tested after 6 weeks of storage:

Wash buffer with thimerosal stored as stock at 4°C for 6 weeks Wash buffer with thimerosal stored as stock at 37°C for 6 weeks

Wash buffer with thimerosal stored as finally diluted buffer at 4°C for 6 weeks Wash buffer with thimerosal stored as finally diluted buffer at 37°C for 6 weeks

Wash buffer with bronidox L stored as stock at 4°C for 6 weeks Wash buffer with bronidox L stored as stock at 37°C for 6 weeks

Wash buffer with bronidox L stored as finally diluted buffer at 4°C for 6 weeks Wash buffer with bronidox L stored as finally diluted buffer at 37°C for 6 weeks

4 ml of each buffer were added to the ready to use bouillon. The bouillon was incubated for 1 week either at 37°C or at 23°C (bacteria or yeast / mould; in total 16 tests) to visually check for microbial growth.

5. Result of the microbial testing

None of the tested buffers showed microbial growth after 1 week of incubation of the bouillons, neither after incubation at 23°C nor at 37°C.

6. Conclusions

The experiments showed that there is no significant difference in stability and functionality between the buffer with thimerosal and with bronidox L. Most importantly, the mean obtained concentrations for the used control samples did not show a significant difference between thimerosal and bronidox L containing wash buffer. The microbial testing showed that both preserving agents effectively prevent microbial growth in the 10fold buffer concentrates and in the finally diluted buffers. Therefore, R-Biopharm AG kindly asks to permit the change of the preserving agent in the wash buffer of the analyzed products. All products are regularly tested over the shelf life by R-Biophahürm’s quality control department.

Exchange ofthimerosal

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