Why chef should keep their fingernails short when they working with food?

Bacteria can easily grow on fingernails, so long nails aren't sanitary enough when cooking for the public as a chef does. Even if one washes their hands frequently, it still doesn't remove the dirt and bacteria from under the fingernails. Also, food tends to get under long nails, and it's more difficult to dice food with long nails because they get in the way.