Is bread a collective noun or common noun?

The noun 'bread' is a common noun, a general word for a type of food.
A collective noun is a noun used to group people or things in a descriptive way, for example, a crowd of people or a mob of people.
A collective noun is also a common noun, a general word for a group.

The standard collective noun for 'bread' is a batch of bread. The noun 'batch' is a common noun.