Fruits & Vegetables:
* Bunch: A bunch of bananas, a bunch of grapes
* Basket: A basket of apples, a basket of tomatoes
* Heap: A heap of potatoes, a heap of oranges
* Pile: A pile of onions, a pile of pears
* Bowl: A bowl of cherries, a bowl of strawberries
Baked Goods:
* Batch: A batch of cookies, a batch of bread
* Loaf: A loaf of bread, a loaf of banana bread
* Dozen: A dozen doughnuts, a dozen muffins
Meat & Seafood:
* Flock: A flock of chickens, a flock of geese (if you're talking about poultry)
* School: A school of fish (if you're thinking of a fish dish)
* Cut: A cut of meat (for example, a cut of beef)
* Portion: A portion of steak, a portion of salmon
Other:
* Box: A box of chocolates, a box of cereal
* Can: A can of soup, a can of beans
* Jar: A jar of pickles, a jar of jam
* Bag: A bag of chips, a bag of flour
Note: Some of these collective nouns can be used with different types of food, but others are more specific. It also depends on how the food is presented. For example, you wouldn't call a group of potatoes a "flock," but you could call a group of chicken nuggets a "flock" if you're being playful.