What Is Kosher? A Complete Guide to Kashrut Laws and Meaning

Almost every food product we buy today is labeled “kosher” — whether it’s falafel, snacks, or dairy products. But what actually stands behind this concept?

The original meaning of the word kosher is “fit” or “proper.” Foods that are permitted by the Torah and prepared according to Jewish law are considered kosher. In this article, we will explore what makes food kosher and the deeper ideas behind the concept.

Kosher Animals

Land Animals

The Torah (Leviticus 11:3) defines kosher land animals as those that have split hooves and chew their cud. These are herbivorous mammals. Common kosher animals today include cows, sheep, and goats, and sometimes deer or buffalo.

Birds

The Torah lists 24 forbidden bird species. The Talmud explains that predatory birds (such as eagles and hawks) are included among them.

In practice, we eat only birds with an established tradition of kashrut, such as chicken, turkey, duck, pigeon, and goose. Eggs are kosher only if they come from kosher birds.

Fish

The Torah (Leviticus 11:9) teaches that kosher fish must have both fins and scales. Even one fin or one scale is sufficient.

Examples of kosher fish include tuna (which has very few scales), carp, tilapia, salmon, cod, and mackerel.

Shellfish, such as shrimp and clams, are not kosher because they lack scales. Marine mammals like whales and dolphins are also not kosher.

Sushi and caviar can be kosher if they come from kosher species and are prepared with kosher utensils.

Insects

The Torah permits only a few specific types of locusts. All other insects are forbidden.

This has practical implications: leafy vegetables (like lettuce, broccoli, and cauliflower) are often infested with bugs and must be carefully checked. Certain fruits, such as raspberries and strawberries, also require inspection and cleaning.

Kosher Slaughter and Preparation

Shechita (Ritual Slaughter)

Even kosher animals must be slaughtered properly. A trained slaughterer (shochet) uses a perfectly sharp knife to cut the trachea and esophagus quickly, minimizing pain.

Inspection

After slaughter, the animal’s internal organs — especially the lungs, are examined for defects that would render it non-kosher (treif).

Removing Forbidden Parts

Certain parts, such as the sciatic nerve (gid hanasheh) and specific fats (chelev), must be removed. This process is complex, so in many cases the hind portion of the animal is sold as non-kosher.

Salting the Meat

The Torah forbids consuming blood (Leviticus 7:26). To remove it, meat is salted for about an hour, allowing the blood to drain, and then thoroughly rinsed.

This must be done within 72 hours of slaughter. Liver, which contains a lot of blood, is usually prepared by broiling over an open flame.

Additional Kashrut Laws

Meat and Milk

The Torah forbids eating, cooking, or benefiting from mixtures of meat and milk.

To avoid this, Jewish kitchens maintain separate utensils for meat and dairy. After eating meat, it is customary to wait six hours before consuming dairy.

Eating Limbs from a Living Animal

The Torah prohibits eating any limb removed from a living animal. This is also one of the Seven Noahide Laws.

Chalav Yisrael (Supervised Milk)

Milk must come from kosher animals and be supervised during milking to ensure its source.

In Israel, this is usually not an issue due to regulation. Abroad, some rely on government supervision, while others insist on direct Jewish oversight.

Food Cooked by Non-Jews

Certain foods cooked by non-Jews (bishul akum) are prohibited to prevent social assimilation.

The general rule is that if a food is inedible raw and important enough to be served at a formal meal, it is forbidden unless a Jew participates in the cooking process.

Kashrut in Plant-Based Foods

Grains (Chadash and Chalah)

• Newly harvested grain (chadash) may not be eaten until after Passover.

• When baking with a significant amount of dough, a portion (chalah) must be separated.

Fruit Trees (Orlah)

Fruit from a tree during its first three years is forbidden. The fourth year requires a special process before consumption.

Tithes (Terumot and Ma’asrot)

Produce grown in Israel must have tithes separated. Untithed produce (tevel) is not kosher.

Shemittah (Sabbatical Year)

Every seventh year, agricultural work in Israel is restricted. Produce grown improperly during this year may not be kosher.

Why Keep Kosher Today?

1. Spiritual Impact

The Torah teaches that non-kosher food affects the soul, limiting spiritual sensitivity and connection.

2. Self-Discipline

Keeping kosher builds self-control by training a person to regulate desires and make mindful choices.

3. Health Considerations

Kosher supervision ensures higher standards of cleanliness and inspection. Certain forbidden foods may also carry health risks.

4. Moral Sensitivity

Kashrut teaches compassion, by minimizing animal suffering and avoiding cruelty.

5. Preserving Identity

Keeping kosher strengthens Jewish identity and continuity. It creates a meaningful boundary that preserves tradition and connection across generations.

Ultimately, the deepest reason for keeping kosher is simple: it is a divine command.

Beyond that, kashrut shapes a person’s body, mind, and soul — elevating even the act of eating into something meaningful and purposeful.