Notice about splitting revolutionary food (6)
I believe the answer is:
cheese
'food' is the definition.
(cheese is a kind of food)
'notice about splitting revolutionary' is the wordplay.
'notice' becomes 'see' (I've seen this before).
'about' shows that the letters should be reversed in order.
'splitting' is an insertion indicator.
'revolutionary' becomes 'che' (Che Guevara the Marxist revolutionary).
'see' in reverse letter order is 'ees'.
'ees' put inside 'che' is 'CHEESE'.
(Other definitions for cheese that I've seen before include "product of cottage industry?" , "Red Leicester" , "Nautical peaked cap - board with wire attached" , "Food from the pressed curd of milk" , "Eg, Camembert" .)