Jews are forbidden to eat blood. These strictures are given to Noah and are further enhanced in Leviticus (17:11, 17:14, & 19:26)
Blood is initially drained at shechita by the shochet. Later the remaining blood is removed by one of two methods :
In handling and processing un-de-blooded meat, all utensils should be used only for that purpose, and not for general cooking.
Broiling is the best method of removing blood. Certain meat where blood is prevalent (liver and already ground meat (which wasn't deblooded before grinding)) can only be prepared this way. Ground meat that is mixed with non-meat material can not be kashered this way. The broiling method is as follows:
Salting is the most popular method of kashering meat. This method uses salt to raise the blood and remove it from the meat. Contrary to popular belief, studies have shown that only a moderate amount of sodium is left residue in the meat. The procedure for salting is as follows:
As can be seen - it is easier to buy your meat from the butcher presalted. Most kosher butchers will provide this service, many with no additional charge.
Eggs carry two rules that must be followed concerning blood.
In addition to blood there are two other parts of the animal that are not eaten. These are :
Meat that is to be eaten must be slaughtered in a particular way (Deuteronomy 12:20 states that slaughter method will be taught to us, and the Oral Law supplies the method). A special prayer is recited before the act. The animal must be slaughtered in a way so that they feel little pain. A razor sharp knife with no nicks is used to cut the esophagus, the trachia, the caratoid arteries, and jugular vein in one cut. The animal is then raised so that the blood flows free. The blood then is covered with dirt (as a show of respect as in the Temple sacrifice). Failure to do any of these renders the animal unfit to eat. Because of the complexity of kosher slaughter a specially trained person (shochet) usually does the ritual.
Hunting animals is thus forbidden by Jewish law. Since the animal is not killed ritually, it is unkosher, and it is considered cruel to kill an animal just for sport.
Another requirement is that the animal be of good health and well taken care of. After slaughter, the shochet will examine the internal organs of the animal for adhesions and disease. Any of abnormality will render the meat unfit. There is a question of minor lesions in the lung. Ashkenazi authorities hold that these lesions are allowable and the meat can be eaten. Sephardi authorities hold that the lung must be smooth ("glatt"). Many Ashkenazi Jews follow the Sephardic practice as a chumra. This practice is the origin of the term glatt kosher.
The animal also must be well taken care of. The practices of mass farming of animals (as with chickens) and the gross mistreatment of animals for food preparation (as with veal industry) renders animals unfit for use. The Torah (and Talmud) are rife with regulations to prevent animal cruelty (e.g. you must feed your animals before you yourself eat, you must not slaughter a parent before the young or vice versa, you can not harness an ox and a donkey together, you can not muzzle an animal being used to tread grain, etc.). Because of kashrut's identification as a reverence for life, these laws are often studied as part of kashrut.