Red food dye (9)
I believe the answer is:
cochineal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">red food dye</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cochineal that I've seen before include "Red food dye (from beetles)" , "Red colour" , "Scarlet food dye" , "Scarlet dye - in a cloche (anag)" , "Red food colouring" .)