According to the information from China Agricultural Machinery Network, a flour mill is a machine used to process flour, and the bran is the leftover crumbs, which generally includes wheat husk and wheat germ, if white flour is found in the bran, this may be because the machine has not been cleaned, and it may be due to a problem with the adjustment of the machine, which leads to a poor separation of the flour, and therefore it will be mixed into the bran.

To solve this problem, the mill needs to be cleaned in detail to completely remove the residual flour and bran, in addition, you can try to adjust the pressure and speed of the mill to get a better separation of the flour and bran, and if there is still the problem of white flour mixed into the bran, you can consider replacing the mill or seeking professional technical advice.