Kosher meat comes from specific animal species, slaughtered by a trained professional using a precise method, then inspected for defects and processed to remove blood. Every step in this chain matters. If any single requirement is missed, the meat is not kosher, regardless of what happened at the other steps.
Which Animals Qualify
For land animals, the rule comes from Leviticus and Deuteronomy: the animal must both chew its cud and have split hooves. Both traits are required. There is no category of “partially kosher.” Cows, sheep, goats, buffalo, deer, and oxen all meet both criteria. Pigs are the most famous example of an animal that fails the test. They have split hooves but don’t chew their cud, so pork can never be kosher regardless of how the animal is slaughtered or processed.
For poultry, the Torah lists specific forbidden birds rather than giving a simple two-part test. In practice, the tradition has settled on a set of domesticated species with a long history of accepted use: chickens, turkeys, ducks, geese, and pigeons. Birds of prey are categorically excluded. The Mishnah describes a non-kosher bird as one that “claws,” meaning it seizes prey with its talons. Kosher birds share a few physical features: an extra rear toe (visible on a chicken foot), a crop for storing food, and a gizzard lined with skin that can be peeled by hand.
Fish must have both fins and scales, which excludes shellfish, catfish, and all crustaceans. Meat from reptiles, insects (with a few exceptions), and amphibians is never kosher.
How the Animal Is Slaughtered
Even a permitted species becomes non-kosher if it isn’t slaughtered correctly. The method is called shechita, and only a trained slaughterer (a shochet) may perform it. The shochet uses a single, uninterrupted stroke across the neck with a specialized knife called a chalaf. This cut severs the trachea, esophagus, carotid arteries, jugular veins, and the vagal nerves in one motion, causing rapid blood loss and loss of consciousness.
The knife itself is subject to exacting standards. It must be razor sharp, perfectly smooth, and completely free of nicks or serrations. The blade has to be at least double the width of the animal’s neck. Before and after every slaughter, the shochet inspects the blade by running a fingernail along both edges. Even a tiny imperfection that a trained knife sharpener might miss can disqualify the meat entirely. If a nick is found after the cut, everything that animal produced is considered non-kosher. The goal is a cut so clean and swift that it minimizes pain by avoiding any dragging or tearing of tissue.
Several specific errors during slaughter also render the meat non-kosher: pausing mid-cut, pressing downward instead of drawing the blade across, cutting outside the designated area of the neck, or tearing rather than slicing. The shochet trains for years to avoid these mistakes.
Inspection After Slaughter
Once the animal is slaughtered, it isn’t automatically cleared. A trained inspector (called a bodek) examines the internal organs for defects that would classify the animal as “trefah,” meaning it had a condition that would have eventually killed it. Jewish law identifies eight categories of fatal defects:
- Puncture from a predator attack that injected venom through the forelegs
- A hole in a vital organ such as the brain, esophagus, or lungs
- A missing organ due to a birth defect
- A removed organ that was torn away during the animal’s life
- A torn stomach lining where the outer meat separates from the large stomach
- Injury from a fall of significant height
- A severed spinal cord
- Broken bones affecting a majority of the ribs or the skull
If the inspector finds any of these conditions, the entire animal is rejected. This post-slaughter inspection is one of the things that distinguishes kosher meat from other religious slaughter traditions.
What “Glatt” Actually Means
You’ve probably seen “Glatt Kosher” on packaging. The word “glatt” is Yiddish for “smooth,” and it refers specifically to the condition of the animal’s lungs. During inspection, the bodek looks for adhesions on the lungs, small fibrous growths that could indicate an underlying hole or weakness. Under the most stringent standard (followed by Sephardic authorities), the lungs must be completely smooth with zero adhesions. A somewhat more lenient standard, historically common among Ashkenazi communities, allows the inspector to gently peel away minor adhesions. If they come off easily and the lung underneath is intact, the meat can still be certified kosher, though not glatt.
Starting around the 1890s, “glatt” began appearing in rabbinic writings, and over time it became the dominant commercial standard. Today, most kosher meat sold in the United States is labeled glatt, and many kosher consumers will only buy meat with this designation.
Removing the Blood
The Torah prohibits consuming blood, so kosher meat goes through a multi-step process called melichah (salting) before it reaches your kitchen. First, the meat is soaked in water for about half an hour. This opens the pores and begins drawing blood to the surface. If the meat sits in the water for more than 24 hours, both the meat and the container are considered non-kosher, because extended soaking is treated as equivalent to cooking, and meat cooked without prior salting is forbidden.
After soaking, the meat is placed on a slanted board, a wicker basket, or straw so blood can drain freely. It’s then thickly salted on all sides. The salt used is coarse (this is actually the origin of the term “kosher salt” in cooking). The meat stays salted for about an hour, though in urgent situations roughly 20 minutes is the minimum. Finally, the salt is shaken off and the meat is rinsed twice. Only then is it ready for cooking.
Liver is an exception. Because it contains so much blood, salting alone isn’t sufficient. Liver must be broiled over an open flame to draw the blood out before it can be eaten.
The Sciatic Nerve and Hindquarter Restriction
Jewish law also prohibits eating the sciatic nerve and surrounding fat, based on the biblical story of Jacob wrestling with an angel and being struck in the hip. In practice, this means the hindquarters of an animal (where the most expensive cuts like filet mignon and sirloin come from) require an extremely skilled and labor-intensive process called “nikkur” to remove the forbidden nerves and fats. In the United States and many other countries, this deveining is so difficult and costly that most kosher producers simply sell the hindquarters to the non-kosher market rather than process them. This is one reason kosher beef tends to come from the front of the animal: chuck, brisket, rib, and shoulder cuts.
Separation From Dairy
Kosher meat cannot be cooked, served, or eaten together with dairy products. This rule extends to the equipment: pots, pans, dishes, and utensils used for meat must be kept separate from those used for dairy. After eating meat, observant Jews typically wait several hours (the exact duration varies by community, ranging from one to six hours) before consuming dairy.
This is why kosher certification symbols on packaging always specify the category. A product marked with an “M” (for meat) or “D” (for dairy) tells consumers at a glance which set of dishes and meals it belongs with. Products that contain neither meat nor dairy are labeled “Pareve,” meaning they can be eaten with either.
How Certification Works
A hechsher is the certification symbol printed on kosher food packaging, and it represents the trademark of the agency that supervised production. For meat, certification means a rabbi or kosher supervisor was present at every critical step: verifying the species, overseeing the slaughter, inspecting the organs, and monitoring the salting and processing. Major agencies like the OU, OK, and Star-K each have their own symbols, and their supervisors regularly visit production facilities.
Not all hechshers carry equal weight in every community. Some consumers only purchase meat certified by agencies known for stricter standards, particularly regarding the glatt requirement and the thoroughness of organ inspections. When buying kosher meat, the certification symbol is the practical shorthand that tells you every link in the chain, from the animal’s species to the final rinse after salting, was verified by someone trained in these laws.