The Jewish dietary laws specifically mention that meat and dairy products have to be kept separate.
This is called Kosher.
The Kosher dietary laws are, in general, fairly straightforward and are based around two central tenets. The first is that meat and dairy products must be cooked and eaten separately. This does not just apply to the food itself; all cutlery, plates, cooking utensils and other implements used in the preparation of the dish are considered tainted if meat and dairy products are combined together in it. This fact leads to kosher kitchens having two or sometimes more sets of utensils; one for cooking meat dishes and another for making dairy creations.