The powdery remnants of breakfast cereal found in the
bottom of the cereal box, which falls from the
bottom of the internal polythene
bag all over the last few whole pieces of cereal you managed to shake out, creating the appearance of a form of gastronomic dandruff upon your morning meal. Originating from, though not limited to, bran-based cereals.
British colloquial term for Cereal Dust.
Alan, did you remember to buy anymore Shreddies? This packs nearly
empty - it's mostly brandruff
left.
I tried to be careful while pouring out the Cheerios, but they still got covered in brandruff.