When eating an apple, it's important to chew slowly. This not only aids digestion but, more importantly, helps maintain oral hygiene.
If it takes you fifteen minutes to finish an apple, the organic acids and fruit acids in the apple can kill bacteria in your mouth. Therefore, eating apples slowly is beneficial to your health.
As for eating candy, some people like to hold a piece of candy in their mouth for several minutes, which is actually a bad habit. This is because the human mouth contains *Lactobacillus*, which can ferment sugar to produce lactic acid. The longer sugar stays in your mouth, the more lactic acid is produced, and the greater the chance of developing cavities.