While I'm not sure, I believe a Bratwurst is already blanched when you buy it, contain mostly pig meat and milk protein.

The sausages are raw. That is, they haven't been preserved or pickled with so-called Poekel (poke) salt. This is a nitrate salt, often used to preserve sausages and cold cuts in Germany. Without this preservative, the sausage or meat turns a natural whitish-grey. They only have put normal table salt in the sausages. A lot of people in Germany don't like the taste of poekel salt, and doctors warn that too much of it causes colon cancer.