Ring work after bit of spoilt seafood (7)
I believe the answer is:
scallop
'spoilt seafood' is the definition.
'scallop' can be an answer for 'seafood' (scallop is a kind of seafood). I'm not sure about the 'spoilt' bit.
'ring work after bit' is the wordplay.
'ring' becomes 'call' (synonyms).
'work' becomes 'op' (common abbreviation for 'opus').
'after' is a charade indicator (letters next to each other).
'bit' becomes 's' (I am not sure about this - if you are sure you should believe this answer much more).
'call'+'op'='callop'
'callop' put after 's' is 'SCALLOP'.
'of' is the link.
(Other definitions for scallop that I've seen before include "Bivalve with radiating ridges on shell" , "Bivalve mollusc with fan-shaped shell" , "Mollusc or lacy edge" , "one may be in one's shell" , "Shellfish that's also plc" .)