Bill McMeekin said:

"Cochineal and saffron spring to mind (more food-dyes than foodstuffs)"

Do tell Bill, what is cochineal used to stain in histology?

Terry L Marshall B.A.(Law), M.B.Ch.B., F.R.C.Path
Consultant Histopathologist
Rotherham General Hospital, Yorkshire
terry.marshall@rgh-tr.trent.nhs.uk