[lostmyface]

An egg that contains a blood spot may not be eaten. This isn't very common, but I find them once in a while. 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.
Forbidden Fats and Nerves

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 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.
Fruits and Vegetables

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.
Separation of Meat and Dairy

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, and the towels on 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. 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

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, thus if you are eating cold food in a non-kosher establishment, the condition of the plates is not an issue. 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. Consult a rabbi for guidance if this situation occurs.
Grape Products

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.

There are a few additional considerations that come up, that you may hear discussed in more sophisticated discussions of kashrut.


Bishul Yisroel
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.
Cholov Yisroel
An ancient rule required that a Jew must be present from the time of milking to the time of bottling to ensure that milk from kosher animals 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. 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. See a more complete discussion under Cholov Yisroel: Does a Neshama Good on the Star-K kosher certification website.
Mevushal
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.


About 25% to 30% of Jews in America keep kosher to one extent or another. This includes the vast majority of people who identify themselves as Orthodox, as well as many Conservative and Reconstructionist Jews and some Reform Jews.

However, the standards that are observed vary substantially from one person to another. According to the 1990 National Jewish Population Survey (NJPS), only about 17% of Jewish families eat kosher meat all the time. (see Table 28 in the survey, if you can find it -- I can no longer locate it online). Others keep kosher more strictly some times than others.

The strictest people will eat only foods that have reliable Orthodox kosher certification, eating only glatt-kosher certified meats and specially certified dairy products. They will not eat cooked food in a restaurant unless the restaurant has reliable Orthodox certification, and they are unlikely to accept an invitation to dinner from anyone who is not known to share their high standards.

Others are more lenient. Some will "ingredients read," accepting grocery store items that do not contain any identifiably non-kosher ingredients. Some will eat cooked food in a restaurant or a non-kosher home, as long as the meal is either vegetarian or uses only kosher meat and no dairy products. Some will eat non-kosher meat in restaurants, but only if the meat comes from a kosher animal and is not served with dairy products. Many of these more lenient people keep stricter standards in their homes than they do in restaurants or in other people's homes.

As rabbi Moline noted, "Everyone who keeps kosher will tell you that his version is the only correct version. Everyone else is either a fanatic or a heretic." . There is a lot of truth in this humorous observation.

hopefuly this was not too long an you all managed to get through it. if you want me to explain anything else i touched on in a similar manner(such as the different forms of judasim) i will be happy to do so.