Kosher Certified: The selection and preparation of foods in accordance with traditional Jewish ritual and dietary laws.
Foods that are not kosher are traife.

The only kosher flesh foods are from animals that chew the cud and have cloven hoofs, such as cattle, sheep, goats, and deer; the hindquarters must not be eaten.
The only fish permitted are those with fins and scales; birds of prey and scavengers are not kosher.
Moreover, the animals must be slaughtered according to ritual, without stunning, before the meat can be considered kosher.