What is Kosher?
The Hebrew word kosher means "fit." The kosher laws define the foods that are fit for consumption for a Jew.
The kosher laws were commanded by Elohim to the Children of Israel in the Sinai desert. Moses taught them to the people and wrote the basics of these laws in Leviticus 11 and Deuteronomy 14; the details and particulars were handed down through the generations and eventually written down in the Mishnah and Talmud.. To these were added various ordinances enacted through the generations by the rabbinical authorities as "safeguards" for the biblical laws.
Throughout our 4000-year history, the observance of kosher has been a hallmark of Jewish identity. Perhaps more than any other "mitzvah," the kosher laws emphasize that Judaism is much more than a "religion" in the conventional sense of the word. To the Jew, holiness is not confined to holy places and times outside the everyday; rather, life in its totality is a sacred endeavor. Even the seemingly mundane activity of eating is a tzadik act and a uniquely Jewish experience.
General Rules
Although the details of kashrut are extensive, the laws all derive from a few fairly simple, straightforward rules:
Certain animals may not be eaten at all. This restriction includes the flesh, organs, eggs and milk of the forbidden animals.
Of the animals that may be eaten, the birds and mammals must be killed in accordance with Jewish law.
All blood must be drained from meat and poultry or broiled out of it before it is eaten.
Certain parts of permitted animals may not be eaten.
Fruits and vegetables are permitted, but must be inspected for bugs (which cannot be eaten)
Meat (the flesh of birds and mammals) cannot be eaten with dairy. Fish, eggs, fruits, vegetables and grains can be eaten with either meat or dairy. (According to some views, fish may not be eaten with meat).
Utensils (including pots and pans and other cooking surfaces) that have come into contact with meat may not be used with dairy, and vice versa. Utensils that have come into contact with non-kosher food may not be used with kosher food. This applies only where the contact occurred while the food was hot.
Grape products made by non-Jews may not be eaten.
There are a few other rules that are not universal.
The Details
Of the "beasts of the earth" (which basically refers to land mammals with the exception of swarming rodents), you may eat any animal that has cloven hooves and chews its cud.
Lev. 11:3; Deut. 14:6.
Cattle, sheep, goats, deer and bison are kosher.
Any land mammal that does not have both of these qualities is forbidden.
The Torah specifies that the camel, the rock badger, the hare and the pig are not kosher because each lacks one of these two qualifications, either the cloven hoof or the chewing of the cud.
`Of the things that are in the waters, you may eat anything that has fins and scales`.
Lev. 11:9; Deut. 14:9.
Fish like tuna, carp, salmon, haddock and herring are all permitted.
Thus, shellfish such as lobsters, oysters, shrimp, clams and crabs are all forbidden.
For birds, the criteria is less clear. The Torah provides a list of forbidden birds (Lev. 11:13-19; Deut. 14:11-18), but does not specify why these particular birds are forbidden.
All of the birds on the forbidden list are birds of prey or scavengers, thus the rabbis inferred that this was the basis for the distinction.
Other birds are permitted for consumption, such as chicken, geese, ducks and turkeys. However, some people avoid turkey, because it was unknown in Ancient Yisrael at the time of the giving of the Torah, leaving room for doubt.
Of the "winged swarming things" (winged insects), a few are specifically permitted (Lev. 11:22), but the Sages are no longer certain which ones they are, so all have been forbidden. There are communities that have a tradition about what species are permitted, and in those communities some insects are eaten.
Rodents, reptiles, amphibians, and insects (except as mentioned above) are all forbidden. Lev. 11:29-30, 42-43.
Some authorities require a post-mortem examination of the lungs of cattle, to determine whether the lungs are free from adhesions. If the lungs are free from such adhesions, the animal is deemed "glatt" (that is, "smooth"). In certain circumstances, an animal can be kosher without being glatt; however, the stringency of keeping "glatt kosher" has become increasingly common in recent years, and you would be hard-pressed to find any kosher meat that is not labeled as "glatt kosher."
As mentioned above, any product derived from these forbidden animals, such as their milk, eggs, fat, or organs, also cannot be eaten. Rennet, an enzyme used to harden cheese, is often obtained from non-kosher animals, thus kosher hard cheese can be difficult to find.
FOR A LIST OF CLEAN AND UNCLEAN FISH AND MEAT-STUFFS GO
_____________________________________