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' suggests taking the first letters (the start - or source - of the word).
'in' is an insertion indicator.
'eggs' becomes 'roe' (fish eggs).
'carried by' indicates putting letters inside.
'greek' becomes 'gr' (abbreviation for Greek).
The initial letter of 'cholesterol' is 'c'.
'c' going inside '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" .)