Revolting whiff surrounds firm, dry cheese (7)
I believe the answer is:
ricotta
'cheese' is the definition.
(ricotta is a type of cheese)
'revolting whiff surrounds firm dry' is the wordplay.
'revolting whiff' becomes 'ria' (I am not sure about this - if you are sure you should believe this answer much more).
'surrounds' means one lot of letters goes inside another.
'firm' becomes 'co' (a firm is a company).
'dry' becomes 'tt' (short for teetotal - no alcohol).
'co'+'tt'='cott'
'ria' placed around 'cott' is 'RICOTTA'.
Can you help me to learn more?
(Other definitions for ricotta that I've seen before include "one brought on board?" , "Italian 4 across" , "may be served with biscuits" , "One soft cheese" , "Read the riot act about the cheese" .)