It would be really nice to have all the food items into one single list but sadly that's the ideal case.
You can try accessing the food synset in WordNet. If you are using NLTK, try:
>>> from nltk.corpus import wordnet as wn
>>> food = wn.synset('food.n.02')
>>> list(set([w for s in food.closure(lambda s:s.hyponyms()) for w in s.lemma_names()]))
