Nikkur and the Forbidden Fats

Shechita and the treifah inspection establish that the animal may be eaten. They do not make the meat fit — two more operations do that: nikkur and melichah.

Nikkur is the removal of the forbidden parts. Three things come out:

1. Chelev — certain fats — together with the forbidden sinews.
2. The blood vessels (chutei dam).
3. The gid hanasheh — the sciatic nerve.

What chelev actually is

Not all fat is forbidden, and the distinction is physical rather than anatomical trivia.

Chelev is fat found in the body particularly around the stomach, kidneys and innards. The operative definition given is:

The forbidden chelev is fat that is separate from the flesh and not together with it — as distinct from permitted fat, which is mixed into the flesh and cannot be separated from it.

So the test is separability. A layer of fat that lifts away is chelev; fat marbled through the muscle is not. Which is why kosher meat can be visibly fatty without any contradiction.

The prohibition covers the chelev of cattle, sheep and goats — "all the chelev of ox, sheep and goat you shall not eat." It does not apply to a kosher chayah, a wild animal: that fat is permitted, and needs no nikkur.

The gid hanasheh

The central nerve of the hind leg, forbidden from the Torah — "therefore the children of Israel shall not eat the gid hanasheh which is on the hip socket."

It applies to cattle, sheep and goats and to kosher chayos, and — the detail that doubles the work — in both the right and the left thigh.

Deveining the blood vessels is likewise done in large and small animals and in kosher chayos. In birds, some have the practice of deveining the neck veins, and some cut them so the blood drains.

Who may do it

This is not an ordinary butchery task.

Nikkur is performed only by a certified menaker, expert in the craft. And two prohibitions follow from that:

• Do not eat meat until you know that what required nikkur has been removed.
• A butcher may not sell meat requiring nikkur before the menaker has done it.

That second one is worth noticing: the obligation sits on the seller, not only on the buyer. Uncleaned meat is not supposed to reach a counter at all.

The three-day window

And there is a time limit that shapes the whole operation.

Nikkur of the chelev is done within three days of shechita, so that the chelev does not harden.

Put the requirements together and you can see why hindquarter nikkur is demanding work rather than routine trimming: it needs a trained specialist, working on both thighs, removing a nerve and an extensive fat and sinew structure, inside a three-day window that is running at the same time as the three-day salting clock.

Those two windows are not independent — the same carcass is against both. Which is why the forequarter is the simpler commercial proposition in many markets, and why hindquarter availability varies so much by place.

For what to establish when buying, see buying and handling meat. Whether a particular cut has been properly cleaned is a question for your rav and your supplier — not something to determine by inspection.