A full set of rules is not covered here, but some of the basics are. Kosher food cannot come from some sources. For instance, bat or pig meat is never kosher. Shellfish, insects and reptiles are also forbidden. Animals killed for their meat must be slaughtered in a certain way. Then, meat and dairy products cannot be eaten together. Vegetables and fruits are kosher, but any insects are not and must be cleaned off. The utensils used to prepare and eat food must also be kosher. Approximately 20% of the Jews in the U.S. keep kosher at home.