Kosher food are food that are deemed clean according to the laws of Moses. One perfect example is Ruminant and non ruminant animals.I must ask, what is special about Kosher food anyhow as a matter of curiosity
Cows, Sheep or any ruminant Beasts are Kosher food. Non ruminant Beasts such as a Pig is not Kosher.
Also creeping things like Lobster and prawns are not Kosher because those creatures are scavengers and carry parasites.
The gist of it is, back in the ancient days these non-kosher food was a method of prevention against illnesses or sickness. It doesn't apply today due to advances in medicines, farming and hygienic living.