A person keeps kosher if he or she follows Jewish Dietary Laws. Jewish Dietary Laws are derived from Biblical laws and rabbinical extensions. The following list summarises these laws:
- Only animals that are ruminant (chew its cud) and have split hooves may be eaten.
- Of the animals that may be eaten, the birds and mammals must be slaughtered in accordance with Jewish law.
- Certain parts of permitted animals may not be eaten.
- All blood must be drained from the meat or broiled out of it before it is eaten.
- Meat (the flesh of birds and mammals) cannot be eaten with dairy.
- Eggs, fruits, vegetables and grains are considered pareve, and can be eaten with either meat or dairy. Fish is also considered pareve, but some kosher observant Jews do not eat fish with meat.
- Utensils that have come into contact with meat (while hot) may not be used with dairy, and vice versa. Utensils that have come into contact with non-kosher food (while hot) may not be used with kosher food.
- Grape products made by non-Jews may not be eaten.
A more detailed explanation can be found at Judaism 101