[0175] The external oxygen data already described for the first 16 hours since the cultivation of L. plantarum (as described earlier) and B. bifidum were gained simultaneously in the same container assembly 200 run and thus, the sample container 18, gassing lid, and external gas sensor were used. It is observable that the DO signal slightly increases from 18 hours, which could be explained by the technically conditioned signal drift of the oxygen optodes with a drift at 0% oxygen of < 0.5% O2 per day. The data of the external oxygen sensor showed a value of 0.029% oxygen in the gas outlet of the container assembly 200 after 23 hours, confirming that the anaerobic cultivation conditions were maintained over the entire cultivation time.