The technical definition of glatt kosher is meat from animals with smooth or defect-free lungs, but today the term glatt kosher is often used informally to imply that a product was processed under a stricter standard of kashrut (the body of Jewish dietary law) . For meat to be kosher, it must come from a kosher animal and be slaughtered in a kosher way. For meat to be glatt kosher, in addition to the two above conditions, the meat must also come from an animal with adhesion-free or smooth lungs.

The word glatt means smooth in Yiddish. In Jewish Law, the term glatt is used to refer to the lungs of animals. After the animal is slaughtered, the animal is opened and examined to determine whether the lungs are smooth. If defects on the lungs are found, the meat is considered treif (torn, mortally injured, non-kosher). If the lungs are found to be defect-free or smooth, the meat is considered to be glatt kosher.

The laws of kashrut, or kosher, are found in the Torah, the Bible itself. For the most part, the only foods subject to kosher laws are animals that are eaten. Though all fruits, vegetables, and growing things are considered kosher, only certain kids of animals are considered kosher.

• Animals that chew their cud, called ruminants, and have split hoofs are kosher. Kosher animals include cows, sheep, deer, lamb, buffalo, and others.
• The only kosher fish are those from species that have fins and scales. These include salmon, tilapia, mahi mahi, trout and many others.
• Only certain birds are kosher. These are all birds that are not birds of prey and conform to the biblical list of kosher birds, such as chicken, turkey and duck.

In order to be up to the highest standards of kosher, caterers and chefs are supervised by rabbis and kosher organizations to be sure everything is done according to the Jewish laws of kashrut. The meat of a fully kosher animal, such as a cow, is not kosher at all if the animal is not slaughtered correctly according to the Jewish laws of shechitah. To be kosher, a shochet (a person who has been specially trained and licensed to slaughter animals and birds in accordance with the laws of shechita) must slaughter the kosher animal according to the Jewish laws with a particular kind of knife and using a special kosher method of slaughter. The shochet must then check to be sure the animal is healthy, since even kosher animals are not considered kosher if they are not healthy enough to live a year on their own. The meat must subsequently be salted to remove any blood, since the blood of the animal and certain parts of its body are not considered kosher.

The mixing of meat and dairy products is strictly forbidden in Jewish law even if both are kosher. Not only can one not make a food of meat and dairy cooked together, but according to Jewish tradition, dairy cannot be eaten immediately after one has eaten meat. This means that a dairy dessert is not acceptable if you are serving a meat as your entrée. It is permissible to eat meat after eating dairy, though not at the same meal.

Some beverages are also subject to the rules of kashrut in Judaism. Though almost all beer is considered kosher if it is not flavored, and most liquor, excluding those that are wine-based, are kosher. Wine or wine-based liquor has some kashrut concerns. Though grapes are a fruit and are not subject to kashrut laws per se, there is a specific kashrut concern associated with wine. The Bible, in its commands to stay far from the worship of idols, forbids the use of things that were used in any idolatrous practice.

In Jewish history, there were times when idolaters would use wine as a libation in pagan religious services. Since wine in ancient days was sold in large barrels, wine would sometimes be used for idolatrous worship and then poured back into the wine barrel and resold as new wine. Thus in the Talmudic period, the rabbis made a halachic, a Jewish legal decree, that wine manufactured by or handled after opening by non-Jewish people had to be treated as if it were not kosher and could not be consumed. The only exception to this rule was wine that had been pasteurized, since it was considered lower in quality and was not, therefore, used in such idolatrous services. As a result of this law pertaining to kosher wine, many kosher wines are pasteurized. This means that it is still considered kosher even if they are opened by non-Jewish waiters. Such wines are known by the term mivushal, "boiled." Sometimes the word mivushal is printed in English on the bottle, but sometimes it is only in Hebrew.

1. The Kosher food market is a $9 billion market today.
2. In 2003, consumers spent approximately $165 billion for kosher products. In comparison, they spent $250 million on kosher products 25 years earlier.
3. The kosher food market is enjoying growth of approximately 15 percent annually. In comparison, non-kosher food sales in American supermarkets are growing at approximately 4% annually.
4. 21% of Americans buy kosher food. Less than 25% of kosher consumers in America are observant Jews. 55% of America's kosher food consumers buy kosher products because they believe kosher food is healthier.
5. Only about 15% of American Jews keep kosher.
6. 80% of all kosher food sales are made outside of the traditional Jewish market. Non-Jewish kosher consumers include health conscience, vegetarians, lactose intolerant, Muslims, Seventh Day Adventists and other Christian sects with dietary restrictions.
7. There are more than 100,000 kosher certified products today. Approximately 3,000 new products are introduced into the kosher market each year. Hebrew National sausages made of 100% beef are the top selling kosher brand in America today.
8. In 2005, 40% of US grocery sales were certified kosher, according to the Bureau of Census. The average number of kosher products in American supermarkets is 17,000.
9. There are over 10,000 kosher producing companies today.
10. There are close to 400 kosher certifiers worldwide. 40% of the retail food products sold in the US today bear some type of kosher certification.