"I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and injustice." is one example of a synecdoche
If the food is a plant then it could be immature. This means that it hasn't yet ripened to its prime, and it's not very tasty when eaten.
Inedible is another possible word. Inedible things can be non-food items such as a bed (you can not eat a bed therefore it is "inedible") or food items that aren't cooked or prepared where it is safe to eat, such as raw meat.
Hope this helped!
~Just a girl in love with Shawn Mendes