Young women in aprons prepare a meal (Soviet Union, 1930s).

Milchik, Fleyshik, and Pareve - Dairy, Meat, and Neutral - The Jewish Kitchen

The basic prohibition against mixing dairy products with meat products is derived through rabbinic interpretation. Why? This rule is derived from the statement in the Torah, "Thou shalt not cook a calf in its mother's milk". The ethical consciousness this rule brings is special. Even if the natural and animal worlds are made to serve humans, it is mandated that there should still be limits to rule Jewish behavior. Because of the exacting rules of kashres, the kosher Jewish kitchen contains many more cooking tools than the average kitchen, since separate meat and dairy dishes and utensils are required.