What is “glatt kosher”?
There are many well-known Jewish interpretations, applications, and traditions associated with the Torah’s dietary laws—ranging from the traditional method of animal slaughter or shechitah, to the separation of meat and dairy, to what is parve, and even to various ethical or homeletical approaches to kosher involving treatment of animals or the environment. Glatt kosher is a highly rigorous application of the Torah’s dietary laws, which not only requires that animals be slaughtered in a particular manner according to the rules of shechitah, but also that the lungs of the animal be entirely smooth. Confusion has definitely set in among many, not only non-Jews investigating kosher but even many Jews, when it is thought that glatt kosher means a hyper-amount of blessings or religious approval given to kosher food items, when in actuality glatt kosher pertains to the quality of the meat that has been butchered.
Alfred J. Kolatch provides the following summary of glatt kosher in his work, The Jewish Book of Why:
“The word glatt is Yiddish for smooth. It refers in talmudic law to the lungs of an animal. If a lung of a slaughtered animal is found to be scarred in any manner, hence not smooth, the lung is examined further to see if there is any break or perforation in the skin. If so, the animal is considered nonkosher.
“Some very observant Jews, however, consider an animal with even the slightest blemish on its lungs to be nonkosher. This group will consume the meat only of animals whose lungs are perfectly smooth. Meat from such animals has come to be known as glatt kosher. The concept has become distorted, however, and all types of kosher foods are now referred to as glatt. This is a misnomer since the word glatt relates specifically to animal foods. A piece of cake or candy or cheese cannot be glatt kosher.”
While there are people in many sectors of the broad Messianic movement who will only eat meat that has an approved hechsher on it, meaning that it has been slaughtered and butchered according to the traditions of shechitah—you will encounter very few who adhere to a level of glatt kosher. Most of those who purchase their meat products from authorized Jewish sources, will be content to follow a level of kosher consistent with either the Conservative and/or Orthodox Jewish communities.
 Alfred J. Kolatch, The Jewish Book of Why (Middle Village, NY: Jonathan David Publishers, 1981), 96.