What is Kosher?

A coworker who is a Kosher Jew has prompted this question. He never can eat any of the lunches provided for conferences and meetings. He asked an odd question today. He seemed interested in the smoked turkey wrap we had for lunch... but he asked if it had cheese on it. I looked at my wrap and answered affirmatively. He turned up his nose at it. Tonight I looked up kosher and kashrut and found out that one of the main kosher laws is that you cannot mix meet and dairy. The dairy cannot have even touched the meat or else they contaminate each other. Furthermore, kosher Jews must have two sets of cooking utensils... one for dairy and one for meat. The two cannot ever be mixed up. Utensils that have touched meat may not touch dairy. Dish washers may not have both meat and dairy dirtied dishes in them. One must wait 3 to 6 hours after eating dairy before eating meat. Kinda strict, eh? There's more rules... maybe I'll write about them later.