Uncontaminated eastern food reduced to a pulp (5)
I believe the answer is:
puree
'to a pulp' is the definition.
(I have seen 'Smooth pulp ' mean 'puree' so perhaps 'pulp' could also mean 'puree')
'uncontaminated eastern' is the wordplay.
'uncontaminated' becomes 'pure' (similar in meaning).
'eastern' becomes 'e'.
'pure'+'e'='PUREE'
'food reduced' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for puree that I've seen before include "creamy mixture" , "processed food?" , "Pulped fruit or vegetables" , "Food passed through a liquidiser" , "Sieved food reduced to pulp" .)