Kosher refers to that which is prepared in accordance with Jewish Law. Kosher foods are foods that practicing Jews are allowed to consume. The specific rules are enumerated in the Torah, and refined in the Talmud.

There are two groups of rules - what can be eaten and how it can be prepared.

If you want to keep things simple, serve a vegetarian meal that excludes either milk or eggs.

What can be eaten

• Any fish that has "both" scales and fins. This means that shellfish are not kosher, and neither are fish like catfish.

• Any land animal that chews its cud "and" has split hooves. Sheep and cows are kosher animals, while pigs and horses and dogs are not kosher. Pigs do have a split hoof, but they do not chew their cud, so they are not kosher. Both deer and goats are kosher if properly slaughtered. There are also restrictions as to what parts of the animal may be eaten. (kosher hot dogs cannot contain some of the filler and miscellaneous scraps that are added to most non-kosher hot dogs)

• There is a list of non kosher birds in the Torah, which names predominantly scavengers and predators. Kosher birds include duck, chicken, and turkey. Ostrich is not kosher.

• There are some kosher insects that are types of grasshopper or locust. Ashkenazi and most Sepharadi groups have lost the tradition of which exact species are kosher, but Yemenites and some Sepharadi groups have maintained this tradition and can properly identify them (though to most people the prospect of eating insects is not appealing, rendering this a largely academic point).

• Animal blood is not to be eaten.

• An animal that is sick or injured cannot be eaten.

• All kosher animals must be slaughtered properly in order for the meat to be permissible.

• There are some restrictions on plants, like they need to be check that there are no insects. And there is problems with products from plants, like grapes.

• Gelatin is usually made from non kosher animal's hooves/bones, but it is possible to get kosher gelatin.

• Ask a local Rabbi for more details.

How it can be Prepared

• It is not enough for an animal to be kosher, that animal must also be slaughtered in a specific way as to minimise the amount of pain dealt to the animal.

• Meat must be "kashered", which removes the blood from the meat. This is done either using salting or roasting. Most kosher meat that one can buy is already kashered.

• Milk and meat cannot be cooked together. This includes eating dairy and meat within certain time periods. Depending on the family's custom, this is 6 hours or 3 hours before consuming dairy products after meat products. Some hold that it is permissible to wash out your mouth before consuming meat products after dairy products, except for hard cheese, with which you wait 1 hour. One must have two entirely different sets of cooking pots and table dishes for milk and meat. Both birds and mammals are considered meat, while fish, insects, and blood-free eggs are considered to be neither dairy or meat. Fish can be eaten with meat or dairy, although some hold that one should not eat fish and meat off of the same dish.

Store Bought Goods

Ever wonder what the U or K in a circle means? Well, those are two of many symbols used by Jews around the world to identify kosher products. A "plain k" [a K all by itself] does not mean that the food is certified kosher, but rather that the company declares it to be kosher using a trustable source. Many Jews do not accept "plain k" as a legitimate kashrut certification.

A list of many of the kosher certification agencies are found here: http://www.kashrut.com/agencies/

Some Jews will not accept certain certifications as interpretations and levels of observance vary from Jew to Jew.

• If you are entertaining for people that you know or think may keep kosher, be sure to ask them about their personal rules, as there are many interpretations and subtle variations that different people will follow. Depending on their observance, they may be fine eating a vegetarian dish cooked in your home, or may not be comfortable doing anything more than eating unprepared fruit.

• A more detailed explanation of Kashrut

Union of Orthodox Congregations, the largest kosher- certification organisation in the USA and other places worldwide.