Some species, such as Penicillium digitatum on citrus fruits, and Penicillium expansum on apples, are common on specific foods, while others are less specialized and grow on many different kinds of food.
Some fungi, like Penicillium digitatum on oranges and Penicillium expansum on pears, tend to be linked to particular foods, while others are more adaptable and can flourish on many different types of food.