Final answer:
The first rule of Jewish dietary laws is not mixing meat and dairy products, and these laws include a variety of other food restrictions, which are part of what defines kosher food.
Step-by-step explanation:
The first rule of Jewish dietary laws, known as kashrut, is not mixing meat and dairy products. These dietary laws, which emerge from the religious beliefs and practices of Judaism, are outlined in the Torah and further developed in later texts such as the Talmud. Foods that comply with these laws are deemed kosher, meaning fit or appropriate for consumption. In addition to prohibiting the mixing of meat and dairy, Jewish dietary laws also include other restrictions such as the avoidance of pork and shellfish, and the requirement for ritual slaughter of animals.