Kosher, otherwise known as "Kashrut," refers to the Jewish laws that dictate which foods can be eaten, and how those foods must be prepared. Most of these rules are laid out in the Torah, as well as the Books of Leviticus and Deuteronomy. Many came about for health and sanitary reasons.

As Judaism 101 points out, a rabbi does not "bless" food in order to make it kosher. Nor is there such a thing as "kosher-style" food -- many traditional Jewish dishes like bagels and matzah ball soup can be non-kosher if not prepared correctly.

While the body of Kashrut law is fairly extensive and detailed, some general themes emerge. Animals that can be eaten must be slaughtered in accordance with Jewish law, and their blood must be drained before consumption. Meat must never be eaten with dairy. And all grape products must be prepared according to Jewish custom.

Which animals are kosher? Ruminants and cloven-hoofed animals are fine. Chicken, turkey, duck, and geese are okay. If it's in the water, it has to have fins and scales. Shellfish are out. Fish and meat can't be eaten together.