Source of cholesterol in eggs carried by Greek shopkeeper (6)
I believe the answer is:
grocer
'shopkeeper' is the definition.
(I've seen this before)
'source of cholesterol in eggs carried by greek' is the wordplay.
'source of' indicates taking the first letters (the start - or source - of the word).
'in' means one lot of letters goes inside another.
'eggs' becomes 'roe' (fish eggs).
'carried by' means one lot of letters goes inside another.
'greek' becomes 'gr' (abbreviation for Greek).
The initial letter of 'cholesterol' is 'c'.
'c' placed into 'roe' is 'roce'.
'roce' placed inside 'gr' is 'GROCER'.
(Other definitions for grocer that I've seen before include "Provisions purveyor" , "Market trader" , "Food dealer" , "Retailer of foodstuffs" , "Retail merchant" .)