Kashrut is the body of Jewish law dealing with what foods we can and cannot eat and how those foods must be prepared and eaten. "Kashrut" comes from the Hebrew root Kaf-Shin-Reish, meaning fit, proper or correct. It is the same root as the more commonly known word "kosher," which describes food that meets these standards. The word "kosher" can also be used, and often is used, to describe ritual objects that are made in accordance with Jewish law and are fit for ritual use.
Contrary to popular misconception, rabbis or other religious officials do not "bless" food to make it kosher. There are blessings that observant Jews recite over food before eating it, but these blessings have nothing to do with making the food kosher. Food can be kosher without a rabbi or priest ever becoming involved with it: the vegetables from your garden are undoubtedly kosher (as long as they don't have any bugs, which are not kosher). However, in our modern world of processed foods, it is difficult to know what ingredients are in your food and how they were processed, so it is helpful to have a rabbi examine the food and its processing and assure kosher consumers that the food is kosher.
Kosher dietary laws are observed all year round, not just during Pesach (Passover). There are additional dietary restrictions during Pesach, and many foods that are kosher for year-round use are not "kosher for Passover." A bagel, for example, can be kosher for year-round use but is certainly not kosher for Passover. Foods that are kosher for Passover, however, are always kosher for year-round use.
There is no such thing as "kosher-style" food. Kosher is not a style of cooking. Chinese food can be kosher if it is prepared in accordance with Jewish law, and there are many fine kosher Chinese restaurants Los Angeles.
Traditional Ashkenazic Jewish foods like knishes, bagels, blintzes, and matzah ball soup can all be non-kosher if not prepared in accordance with Jewish law. When a restaurant calls itself "kosher-style," it usually means that the restaurant serves these traditional Jewish foods, and it almost invariably means that the food is not actually kosher.
Food that is not kosher is commonly referred to as treif (lit. torn, from the commandment not to eat animals that have been torn by other animals).
Many modern Jews think that the laws of kashrut are simply primitive health regulations that have become obsolete with modern methods of food preparation. There is no question that some of the dietary laws have some beneficial health effects. For example, the laws regarding kosher slaughter are so sanitary that kosher butchers and slaughterhouses have been exempted from many USDA regulations.
However, health is not the only reason for Jewish dietary laws. Many of the laws of kashrut have no known connection with health. To the best of our modern scientific knowledge, there is no reason why camel or rabbit meat (both treif) is any less healthy than cow or goat meat. In addition, some of the health benefits to be derived from kashrut were not made obsolete by the refrigerator. For example, there is some evidence that eating meat and dairy together interferes with digestion, and no modern food preparation technique reproduces the health benefit of the kosher law of eating them separately.
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.
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. 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. Cattle, sheep, goats, deer and bison are kosher.
Of the things that are in the waters, you may eat anything that has fins and scales. Lev. 11:9; Deut. 14:9. Thus, shellfish such as lobsters, oysters, shrimp, clams and crabs are all forbidden. Fish like tuna, carp, salmon and herring are all permitted. 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 list are birds of prey or scavengers, thus the rabbis inferred that this was the basis for the distinction. Other birds are permitted, such as chicken, geese, ducks and turkeys. However, some people avoid turkey, because it is was unknown 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.
The mammals and birds that may be eaten must be slaughtered in accordance with Jewish law. (Deut. 12:21). We may not eat animals that died of natural causes (Deut. 14:21) or that were killed by other animals. In addition, the animal must have no disease or flaws in the organs at the time of slaughter. These restrictions do not apply to fish; only to the flocks and herds (Num. 11:22).
Ritual slaughter is known as shechitah, and the person who performs the slaughter is called a shochet, both from the Hebrew root Shin-Cheit-Teit. The method of slaughter is a quick, deep stroke across the throat with a perfectly sharp blade with no nicks or unevenness. This method is painless, causes unconsciousness within two seconds, and is widely recognized as the most humane method of slaughter possible.
Another advantage of shechitah is that it ensures rapid, complete draining of the blood, which is also necessary to render the meat kosher.
The shochet is not simply a butcher; he must be a pious man, well-trained in Jewish law, particularly as it relates to kashrut. In smaller, more remote communities, the rabbi and the shochet were often the same person.
The Torah prohibits consumption of blood. Lev. 7:26-27; Lev. 17:10-14. This is the only dietary law that has a reason specified in Torah: we do not eat blood because the life of the animal (literally, the soul of the animal) is contained in the blood. This applies only to the blood of birds and mammals, not to fish blood. Thus, it is necessary to remove all blood from the flesh of kosher animals.
The first step in this process occurs at the time of slaughter. As discussed above, shechitah allows for rapid draining of most of the blood.
The remaining blood must be removed, either by broiling or soaking and salting. Liver may only be kashered by the broiling method, because it has so much blood in it and such complex blood vessels. This final process must be completed within 72 hours after slaughter, and before the meat is frozen or ground. Most butchers and all frozen food vendors take care of the soaking and salting for you, but you should always check this when you are buying someplace you are unfamiliar with. An egg that contains a blood spot may not be eaten. It is a good idea to break an egg into a glass and check it before you put it into a heated pan, because if you put a blood-stained egg into a heated pan, the pan becomes non-kosher. If your recipe calls for multiple eggs, break each one into the glass separately, so you don't waste all of the eggs if the last one is not kosher.
The sciatic nerve and its adjoining blood vessels may not be eaten. The process of removing this nerve is time consuming and not cost-effective, so most American kosher slaughterers simply sell the hind quarters to non-kosher butchers. A certain kind of fat, known as chelev, which surrounds the vital organs and the liver, may not be eaten. Kosher butchers remove this. Modern scientists have found biochemical differences between this type of fat and the permissible fat around the muscles and under the skin.
All fruits and vegetables are kosher (but see the note regarding Grape Products below). However, bugs and worms that may be found in some fruits and vegetables are not kosher. Fruits and vegetables that are prone to this sort of thing should be inspected to ensure that they contain no bugs. Leafy vegetables like lettuce and herbs and flowery vegetables like broccoli and cauliflower are particularly prone to bugs and should be inspected carefully. Strawberries and raspberries can also be problematic. The Star-K kosher certification organization has a very nice overview of the fruits and vegetables prone to this and the procedure for addressing it in each type.
The restrictions on grape products derive from the laws against using products of idolatry. Wine was commonly used in the rituals of all ancient religions, and wine was routinely sanctified for pagan purposes while it was being processed. For this reason, use of wines and other grape products made by non-Jews was prohibited. (Whole grapes are not a problem, nor are whole grapes in fruit cocktail).
For the most part, this rule only affects wine and grape juice. This becomes a concern with many fruit drinks or fruit-flavored drinks, which are often sweetened with grape juice. You may also notice that some baking powders are not kosher, because baking powder is sometimes made with cream of tartar, a by-product of wine making. All beer used to be kosher, but this is no longer the case because fruity beers made with grape products have become more common.
On three separate occasions, the Torah tells us not to "boil a kid in its mother's milk." (Ex. 23:19; Ex. 34:26; Deut. 14:21). The Oral Torah explains that this passage prohibits eating meat and dairy together. The rabbis extended this prohibition to include not eating milk and poultry together. In addition, the Talmud prohibits cooking meat and fish together or serving them on the same plates, because it is considered to be unhealthy. It is, however, permissible to eat fish and dairy together, and it is quite common (lox and cream cheese, for example). It is also permissible to eat dairy and eggs together.
This separation includes not only the foods themselves, but the utensils, pots and pans with which they are cooked, the plates and flatware from which they are eaten, the dishwashers or dishpans in which they are cleaned, the sponges with which they are cleaned and the towels with which they are dried. A kosher household will have at least two sets of pots, pans and dishes: one for meat and one for dairy. See Utensils below for more details.
One must wait a significant amount of time between eating meat and dairy. Opinions differ, and vary from three to six hours after meat. This is because fatty residues and meat particles tend to cling to the mouth. From dairy to meat, however, one need only rinse one's mouth and eat a neutral solid like bread, unless the dairy product in question is also of a type that tends to stick in the mouth.
The Yiddish words fleishik (meat), milchik (dairy) and pareve (neutral) are commonly used to describe food or utensils that fall into one of those categories.
Note that even the smallest quantity of dairy (or meat) in something renders it entirely dairy (or meat) for purposes of kashrut. For example, most margarines are dairy for kosher purposes, because they contain a small quantity of whey or other dairy products to give it a buttery taste. Animal fat is considered meat for purposes of kashrut. You should read the ingredients very carefully, even if the product is kosher-certified.
Utensils (pots, pans, plates, flatware, etc., etc.) must also be kosher. A utensil picks up the kosher "status" (meat, dairy, pareve, or treif) of the food that is cooked in it or eaten off of it, and transmits that status back to the next food that is cooked in it or eaten off of it. Thus, if you cook chicken soup in a saucepan, the pan becomes meat. If you thereafter use the same saucepan to heat up some warm milk, the fleishik status of the pan is transmitted to the milk, and the milchik status of the milk is transmitted to the pan, making both the pan and the milk a forbidden mixture.
Kosher status can be transmitted from the food to the utensil or from the utensil to the food only in the presence of heat, (including hot spices) or prolonged contact, thus if you are eating cold food in a non-kosher establishment, the condition of the plates is not an issue. I knew an Orthodox rabbi who would eat ice cream at Friendly's, for example, because the ice cream was kosher and the utensils are irrelevant for such cold food. Likewise, you could use the same knife to slice cold cuts and cheese, as long as you clean it in between, but this is not really a recommended procedure, because it increases the likelihood of mistakes.
Stove tops and sinks routinely become non-kosher utensils, because they routinely come in contact with both meat and dairy in the presence of heat. It is necessary, therefore, to use dishpans when cleaning dishes (don't soak them directly in the sink) and to use separate spoon rests and trivets when putting things down on the stove top.
Dishwashers are a kashrut problem. If you are going to use a dishwasher for both meat and dairy in a kosher home, you either need to have separate dish racks or you need to run the dishwasher in between meat and dairy loads. You should use separate towels and pot holders for meat and dairy. Routine laundering kashers such items, so you can simply launder them between using them for meat and dairy.
Certain kinds of utensils can be "kashered" if you make a mistake and use it with both meat and dairy.
There are a few additional considerations that come up, that you may hear discussed in more sophisticated discussions of kashrut.
In certain circumstances, a Jew (that is, someone who is required to keep kosher) must be involved in the preparation of food for it to be kosher. This rule is discussed in depth under Food Fit for a King on the Star-K kosher certification website.
An ancient rule required that a Jew must be present from the time of milking to the time of bottling to ensure that the milk actually came from kosher animals and did not become mixed with milk from non-kosher animals. Milk that is observed in this way is referred to as Cholov Yisroel, and some people will consume only Cholov Yisroel dairy products. However, in the United States, federal law relating to the production of milk is so strict that many Orthodox sources accept any milk as kosher. You will sometimes see high-level discussions of kashrut address whether a product is Cholov Yisroel or non-Cholov Yisroel.
Most kosher wines in America are made using a process of pasteurization called mevushal, which addresses some of the kashrut issues related to grape beverages. See The Art of Kosher Wine Making on the Star-K kosher certification website.
Written by Tracey R Rich: http://www.jewfaq.org/kashrut.htm.
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