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The most well-known of all Jewish religious practices is that of eating only foods that are "kosher." The laws of kashrut - that is Jewish dietary laws, which are part of the 613 commandments - can seem puzzling or arbitrary to the outsider, but they have held great meaning throughout Jewish history.

In Judaism, for those who keep kosher, observance of the dietary laws is both an opportunity for obedience to God and for preserving Jewish unity and identity. The importance of the laws of kashrut to the Jewish people has been demonstrated in times of persecution, in which Jews have been forced to eat non-kosher foods (usually pork) under penalty of death: many Jews chose to die rather than break kosher.

Kosher Terminology

Kosher is central to Jewish beliefs. The word "kosher" is the Anglicized form of the Hebrew kasher, which literally means "good" or "proper," but came to indicate an item "fit for ritual use." Kashrut thus means "fitness" for ritual use. The Hebrew word for non-kosher is trayf, from the word terayfa, "torn" (from the commandment not to eat meat that has been "torn" by other animals).

Incidentally, the phrase "kosher-style food" that is sometimes used to refer to traditional Jewish fare like blintzes and matzah ball soup, is not really accurate. There is no such thing as "kosher style," since any style of food may be kosher or non-kosher, from Chinese to Mexican to Jewish food.

Kosher Observance Today

Not all Jews obey the dietary laws, or "keep kosher"; sometimes their observance depends on what denomination of Judaism they belong to. Most Reform Jews consider the laws of kashrut to be an outdated ritual and ignore them completely. Others keep kosher at home, but not while dining out or at someone else's home. Orthodox Jews fully obey the laws of kashrut, believing that they are divine laws for all time and all places. Conservative Jews tend to keep kosher consistently as well, although their rules of kashrut are slightly less strict than those of Orthodox Jews.

How to Keep Kosher: The Laws of Kashrut

The following table summarizes the classification of foods under the laws of kashrut.

These prohibitions derive from specific instructions in the Torah, primarily in Deuteronomy and Leviticus. These instructions were then interpreted, expanded and modified by rabbis as Jews encountered new cultures and situations.

All fruits, vegetables and grains are permissible (Gen. 1:29), with the exception of grape products. Due to laws against eating or drinking anything offered to idols, and the fact that wine was often made for pagan offerings and celebrations, all wine and grape juice that is not made under Jewish supervision is prohibited.

Only animals that chew their cud and have cloven hooves are kosher (Lev. 11:3; Deut. 14:6). Thus beef, sheep, lamb, goats and deer may be eaten, while pork, camel and rabbits may not. These restrictions include the flesh, organs, milk and any by-products. Thus gelatin, which is usually made from horse hooves, is trayf, as are most hard cheeses, which are processed using an enzyme from the stomach lining of non-kosher animals.

These animals must have no disease or flaws (Num. 11:22). Many ritual slaughterhouses perform post-mortem examination's of the lungs for adhesions. Animals free of these adhesions are designated glatt ("smooth") kosher.

Kosher animals must be ritually slaughtered in order to remain kosher (Deut. 12:21). The primary goal of ritual slaughter is to rid the animal of as much blood as possible, for ingesting blood is forbidden by the Torah. Ritual slaughter involves cutting the animal's throat with an extremely sharp knife with no nicks (this is regarded as the most humane method of slaughter). The meat must then be kashered, or made kosher, by hanging the carcass to drain as much blood as possible. The meat must then be washed, salted ("kosher salt" is designed for this purpose), and cooked well-done.

Certain parts of kosher animals are non-kosher. One such part is the sciatic nerve in the hindquarters, which is extremely difficult to remove. Thus some of the choicest cuts of meat - like filet mignon and sirloin steak - are forbidden. The fat surrounding the animal's organs is also trayf. Interestingly, there is a biochemical difference between the this fat and the fat surrounding the muscles (which is kosher).

Only domesticated fowl such as chicken, turkey, quail and geese may be eaten. Birds of prey and scavenger birds, such as eagles, hawks and vultures, are prohibited (Lev. 11:13-19; Deut. 14:11-18).

Only seafood with fins and scales are kosher. This rules out calimari and octopus and all shellfish, such as crab, lobster, clams. Sturgeon and shellfish have also been added to the list, as their scales are questionable. Fish need not be ritually slaughtered (Num. 11:22).

No insects may be eaten (Lev. 11:12). The Torah allows for certain exceptions, but since the rabbis have not been able to determine which these are, all have been forbidden. Although this sounds like a rule anyone would be more than happy to follow, remember that many additives and food colorings are made from insects.

Meat and dairy products may not be combined or eaten at the same meal. Although the Torah merely prohibits boiling a goat in its mother's milk (Ex. 23:19; Ex. 34:26; Deut. 14:21), the Talmud interprets this as forbidding meat and dairy to be eaten together. However, fish with dairy or eggs with dairy are permitted. The Yiddish words fleishig (meat), milshig (dairy) are used to designate foods for which this law must be kept in mind. Even the smallest amounts of meat or dairy matter, so margarine (which uses small amounts of whey) would be considered a dairy product for kashrut purposes. Pareve (neutral) designates foods that contain neither meat nor dairy and can therefore be eaten with either one.

What constitutes a "separate meal"? Opinions differ a bit as to the details, but most Jews wait between three to six hours after a meat meal before consuming dairy products. This is because remnants of meat or fat tend to remain in the mouth for several hours. By contrast, one need only rinse one's mouth and eat a pareve food after consuming dairy products to be able to eat meat.

The kashrut extends to non-food products. Utensils like pots, pans, sinks, dishwashers, potholders and plates take on the status (fleishig, milshig, treyf or pareve) of the food they touch in the presence of heat. For example, a pan used to fry a hamburger or a pot used to make stew become fleishig. If the fleishig pot or pan is then used to boil milk, the kashrut has been violated. Similarly, a bowl previously used for chicken soup cannot be used for ice cream. When eating foods prepared away from home, Jews keeping kosher must ensure utensils have not been used to prepare non-kosher foods.

For this reason, most kosher households have at least two sets of dishes, one for meat and one for dairy. Cleaning is also important - separate dishpans, sponges, dish racks and dishwasher loads must be used for fleishig and milshig items. To kasher a utensil, or make it usable for any purpose, it must either be heated to a very high temperature (450°) or soaked in water for several days. Regular laundering kashers items such as pot holders and towels.

Since the presence of heat is required for the transfer of status from food to utensil and vice versa, cold food may be eaten on a clean plate regardless of its status, and the same knife may be used to cut meat and cheese, so long as it is cleaned in between.

Being a Kosher Consumer

Most Conservative Jews are satisfied to read product ingredient labels to make sure their food is kosher, while Orthodox Jews tend to insist that foods be certified kosher by a trained rabbi, called a mashgiach. The "seal of approval" that indicates a mashgiach has observed and approved the product's preparation is called a hechsher.

Several Jewish symbols are used to indicate such approval. The most common are K inside a circle, which stands for "kosher," and a U inside a circle, the certification symbol of the Union of Orthodox Jewish Congregations.

Other Jewish-oriented symbols include a P inside a circle, which denotes a food fit for Passover (when fermented foods are not permitted), the letter "M" to indicate a meat product, the letter "D" to indicate a dairy product, and the word "pareve" or "parev," which indicate a pareve or neutral food.

The letter "K" by itself does not indicate approval by a mashgiach. Since a letter cannot be trademarked, any product can carry a "K" on its label. All this indicates, therefore, is that the manufacturer is certifying that the product is kosher. Many such products, however, are decidedly non-kosher, so kosher consumers should be wary of this symbol.

The Purpose of Kashrut

The Torah offers no explanation for the dietary laws other than the holiness of God and his chosen people. "You are to be holy to me because I, the Lord, am holy, and I have set you apart from the nations to be my own" (Lev. 20:26). Nonetheless, various other speculations have been offered by Jews and non-Jews alike.

Many believe the Jewish dietary laws to be primitive health regulations. This theory is supported by the fact that obeying the kashrut offers many health benefits. Some are obvious: rodents and insects are notorious as disease-carriers, and a discovered carcass is likely to be rotting and unsanitary. Some benefits have only come to light recently: the parasitic disease trichinosis has been linked to pork, the method of ritual slaughter is so sanitary that kosher slaughterhouses have been exempted from many USDA regulations, and there is even evidence that consuming meat with dairy products interferes with digestion. However, health benefits do not explain all the laws of kashrut. There are no known health problems associated with eating camel and rabbit, for example.

One definite benefit of the kashrut is that it serves to keep the Jewish people separate and distinct from their surrounding culture. From a religious perspective, the dietary laws were God's way of unifying his chosen people and preserving them from assimilation. This notion is suggested by the Torah, as seen in the verse quoted above. From a secular perspective, the dietary laws provide a sense of unity and force Jews to rely on one another, which contributes to the survival of the group.

Kashrut also cultivates self-control and discipline, and encourages mindful eating. The great Jewish philosophy Maimonides wrote that the dietary laws "train us to master our appetites, to accustom us to restrain our desires, and to avoid considering the pleasure of eating and drinking as the goal of man's existence."

Given its regulations for humane slaughter and the many restrictions on meat-eating, many Jews have concluded that the kashrut teaches reverence for animal life. Some say it even encourages vegetarianism, which is given as the ideal in Genesis 1:29 and will again prevail in the messianic age.

Finally, and perhaps most importantly, keeping kosher is an act of faith and obedience to God. Jews may not understand why God has given these regulations, but he has done so, and he is to be trusted and obeyed. The laws of kashrut thus provide the opportunity to incorporate religious ritual and the sacred into a necessary daily activity.

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