Why can Jews not eat bacon?

According to Jewish religious law or kashrut, Jews cannot eat bacon or any kind of pork (Leviticus 11:7–8; Deuteronomy 14:8), or shellfish of any kind, nor certain meats, poultry, and fish. Additionally, pork is regarded as "treif" according to Jewish dietary laws. Treif, which comes from the biblical words toreif or terefah, essentially defines all foods forbidden (not kosher) under Jewish law.