FID Questions

I have another question to a certain food, I was wondering if yeast (whether in the form of yeast dough or in the form of yeast flakes for vegan cooking) is allowed or can be tested after the FID program. Like if there can be a "yeast testing day" added after completing all the other tests.

And another question for fermented foods, when is the best time to test them?

Thank you so much in advance and greetings from Europe :)