Separation of Milk and Meat
Meat and milk should not be cooked or eaten together; this applies to any mixture of meat, poultry or any part or derivative of an animal or bird with milk or any milk product or derivative.
Anything which is neither milky or meaty is called parev and may be eaten with either milk or meat (although meat and fish should not be served on the same plate).
It's wise to check even when you think it's obvious. For example, some bread and some plain chocolate contains milk, margarine often contains milk or milk derivatives and milk substitutes often contain some milk!
After eating meat, oneis meant to wait until the next meal, before eating anything containing milk. The definition of between meals varied from country to country in Europe and elsewhere so that waiting periods of one, three and six hours are commonly found.
The most distinctive feature of a kosher kitchen is the poseession of two sets ofutensils, for meat and milk. You will need seperate dishes, pots, cutlery etc as well as washing up bowls and brushes, draining racks and dishcloths. The two sets should be easily distinguishable from each other. Meat and milk utensils should also be stroed seperately, on different shelves, or preferably in different cupboards.
Utensils used for neither milk nor meat are called parev and should also be kept seperately and not ew washed with either milk or meat.
While preparing or eating food, various steps are usually taken to avoid confusion: meaty and milky foods or utensils are not put on the same surface at the same time, unless the surface is divided.
Pareve food cooked in a meaty pot is not eaten together with milk (and vice versa) though it is not considered meaty to the extent of having to wait before eating milk.
An oven or grill should not be used for meaty and milky food at the same time; this is not merely because of confusion bu because such food would be considered to be a mixture of neat and milk and, as such, could not be eaten. An oven which has been used for uncovered meat should in fact undergo a kashering process before being used for milk (or vice versa); this simply means that, having been thoroughly cleaned if necessary, the oven is put on its highest heat for half an hour.
A vessel that has been used for a hot non kosher substance (over 45C) is assumed to have absorbed the taste of that substance and to impart it to any new substance put into it hot, thereby rendering it non kosher.