Spain to block dairy product (4)
I believe the answer is:
edam
'dairy product' is the definition.
(Edam is an example)
'spain to block' is the wordplay.
'spain' becomes 'e' (abbreviation for Espana).
'to block' becomes 'dam' (damming is a kind of blocking).
'e'+'dam'='EDAM'
(Other definitions for edam that I've seen before include "Cheese made in Holland" , "something from the deli" , "Dutch specialty" , "Madeinto popular cheese" , "Mild yellow Dutch cheese" .)