Toxins

Some kinds of raw beans, especially red and kidney beans, contain a harmful toxin (lectin phytohaemagglutinin) that must be removed by cooking. A recommended method is to boil the beans for at least ten minutes; undercooked beans may be more toxic than raw beans. Cooking beans in a slow cooker, because of the lower temperatures often used, may not destroy toxins even though the beans do not smell or taste bad (though this should not be a problem if the food reaches boiling temperature and stays there for some time).