Food spoilt, alas, by many (5)
I believe the answer is:
salad
'food' is the definition.
(I know that salad is a type of dish)
'spoilt alas by many' is the wordplay.
'spoilt' is an anagram indicator.
'by' says to put letters next to each other.
'many' becomes 'd' ().
'alas' with letters rearranged gives 'sala'.
'sala'+'d'='SALAD'
(Other definitions for salad that I've seen before include "- Days (musical)" , "rabbit food" , "Mixed food" , "A dish of lettuce and vegetables" , "Counter serving cold vegetable dishes" .)