Some hamburgers about to be served as common food (4)
I believe the answer is:
grub
'common food' is the definition.
(I've seen this before)
'some hamburgers about' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'about' is a reversal indicator.
'burg' can be found hidden inside 'hamburgers'.
'burg' in reverse letter order is 'GRUB'.
'to be served as' acts as a link.
(Other definitions for grub that I've seen before include "Worm-like larva of an insect" , "Common food" , "Slangy food or kind of larva" , "Food (informal)" , "Food - worm" .)