For food to be considered kosher there are many guidelines that must be followed. Kashrut, the Jewish law concerning food items, details which foods can be consumed, what they can be consumed with and all aspects of how they are harvested and prepared. But to enjoy a fantastic meal in a kosher restaurant, all you need to understand are a few basics which will make you more comfortable and also will allow you to show respect for the practices of the religion.
Meat and Dairy
One of the more difficult rules for many non-Jews to grasp is that most kosher restaurants can serve either meat or dairy products but not both. This is because meat and dairy are never supposed to come into contact with one another. Food preparation rules go so far as to state that any item that come into contact with meat shall never come into contact with dairy. This includes cutlery, plates, cookware and dishes. So if the restaurant does serve both, guests should be very respectful and keep all of the meat utensils separate from the dairy ones. Also, if the restaurant only serves meat items, remember that items such as butter would not be available but a dairy free substitute often is. Likewise, a dairy restaurant is likely to offer a vegetarian meat substitute.
It is rare that any outside food is ever welcome at a restaurant but sometimes with small children it is accepted. If this is the case, you should be mindful of the type of food that the restaurant serves and not contaminate the kosher dishes or silverware with food that you have brought in.
A short bit of research and a little bit of effort to show respect for practices that have been followed for over 3,000 years will be greatly appreciated by the owners of any kosher restaurant.