Kashrut
Among the numerous laws that form "kashrut" are prohibitions on the consumption of certain animals (such as pork and shellfish), mixtures of meat and milk, and the commandment to slaughter mammals and birds according to a process known as "shechita". There are also laws regarding agricultural produce that might impact the suitability of food for consumption.
Jewish humor
For example: One Jewish Chełm resident bought a fish on Friday in order to cook it for Sabbath. He put the live fish underneath his coat and the fish slapped his face with his tail. He went to the Chełm court to submit a charge and the court sentenced the fish to death by drowning.