How is something kosher?

Food is kosher when it is prepared and consumed according to the laws of kashrut. The core rules of kashrut (dietary laws) are:

* Land animals must have split hooves and chew their cud.

* Fish have to have scales and fins.

* Birds cannot be amongst those listed as forbidden in the Torah and cannot be hunters/scavengers

* Animals must be killed in a specific manner and must be free of all disease

* As much blood as possible must be removed from meat as consumption of blood is forbidden

* Dairy and meat cannot be combined in the same meal and there's a waiting period between eating one then the other.

* Orthodox Jews and some Conservative Jews will not eat certain fruits and vegetables because it's too difficult to guarantee that all bugs have been washed away (cauliflower, asparagus, and the like).

Additionally, food must be prepared and handled following kashrut. Any food that does not meet these requirements cannot be eaten by those who are religiously observant.