Where food's prepared in high-vis vest? (7)
I believe the answer is:
worktop
I believe this clue is a double definition.
'where food's prepared' is the first definition.
(kitchen worktop)
'high-vis vest?' is the second definition.
(top worn at work)
'in' acts as a link.
(Other definitions for worktop that I've seen before include "Surface on which to toil" , "Practical surface" , "Surface in kitchen for preparation, etc" , "Kitchen unit surface" , "E.g. kitchen surface" .)