To me, that aspect of life that most touches the everyday and celebrations is food.

Food is never static; culture is never static.

The knish is a classic example of peasant food evolving into comfort food and even sophisticated fare.

The processing and preparation of food can transform a kosher item into a non-kosher item.

A Jewish food is one that is almost sanctified, either by its repeated use or use within the holidays or rituals. So food that may have not been Jewish at one point can become Jewish within the cultural context.

Judaism is not, per se, a religion in the sense most Americans think of. Even if you don't adhere to the various precepts, you're still a Jew.