Food mum fed to dog in Oz (6)
I believe the answer is:
tomato
'food' is the definition.
(tomato is a kind of food)
'mum fed to dog in oz' is the wordplay.
'mum' becomes 'ma' (ma can mean mother).
'fed to' means one lot of letters goes inside another.
'dog in oz' becomes 'toto' (I've seen this in another clue).
'ma' placed within 'toto' is 'TOMATO'.
(Other definitions for tomato that I've seen before include "Pulpy fruit eaten as vegetable" , "that's suitable to eat" , "A glossy red fruit eaten as a vegetable" , ""Plum" or "beef" fruit?" , "It's also known as a love apple" .)