Local bacteria, S. mutans ingest fermentable carbohydrates decreasing plaque pH. Similarly, any food or beverage that contains fermentable carbohydrates, consumed over a prolonged period, or with increased frequency will have the same effect. Fruits in general tend to have low cariogenic potential, with the exception of dried fruits and certain fresh fruits. Apples, bananas, and grapes contain 10-15% sucrose, citrus fruit 8%, and berries and pears only 2%. Although citrus fruits are high in water, stimulate saliva production, and provide an excellent source of vitamin C, they can potentially erode tooth enamel if consumed in large quantities over an extended period of time.