Swallow discovered in catering establishment (6)
I believe the answer is:
ingest
'swallow' is the definition.
(I've seen this before)
'discovered in catering establishment' is the wordplay.
'discovered' says the answer is hidden in the clue (remove the letters covering the answer in the clue).
'INGEST' can be found hidden inside 'in catering establishment'.
(Other definitions for ingest that I've seen before include "Swallow, absorb" , "Take nourishment into the body" , "Absorb mentally" , "Take in with tinges" , "Scoff" .)