CSENGELE, Hungary — In a small room lined with religious texts, a rabbi demonstrates how knives are sharpened and inspected before they are put to use slitting the throats of chickens, geese and other poultry at a kosher slaughterhouse in Hungary.

A shochet, someone trained and certified to slaughter animals according to Jewish tradition, whets a knife on increasingly fine stones before drawing the blade across a fingernail to feel for any imperfections in the steel that might inhibit a smooth, clean cut and cause unnecessary pain.

“One of the most important things in kosher is that the animal doesn’t suffer,” said Rabbi Jacob Werchow, who oversees production at Quality Poultry, a 3 1/2-year-old slaughterhouse that supplies nearly 40% of Europe’s kosher poultry market and a large portion of the foie gras sold in Israel.

The methods employed at the facility are based on ancient Judaic principles commanding the humane treatment of living creatures. They also are at the center of a debate about how to balance animal rights and religious rights as parts of Europe limit or effectively ban the ritual slaughter practices of Jews and Muslims.

Companies like Quality Poultry have found new export markets since the European Union’s highest court last month upheld a law in Belgium’s Flanders region that prohibited slaughtering animals without first stunning them into unconsciousness. But the European Court of Justice ruling also has provoked fears of eventual EU-wide prohibitions on ritual slaughter, and aroused memories of periods when Europe’s Jews faced cruel persecution.

“This decision doesn’t only affect the Belgian Jewish community, it affects all of us,” said Rabbi Slomo Koves of the Association of Hungarian Jewish Communities, which owns the slaughterhouse. “If this is the case in Belgium and the court has given it moral approval, that might start a process on a larger scale. If you go down this logic, the next step is you also cannot not sell meat like this in these countries.”

Animal rights groups say that slitting the throats of livestock and poultry birds while they are conscious causes suffering that amounts to animal cruelty. Stunning methods vary, but the procedure most often is performed through electric shock or a bolt pistol to the animal’s skull.

“Reversible stunning is the bare minimum we can do to protect animals,” said Reineke Hameleers, CEO of the Brussels-based Eurogroup for Animals. “They should be rendered unconscious before being killed.”

The situation is not so cut-and-dried for religious observers. Jewish law forbids injury or damage to animal tissues before slaughter, and modern stunning practices can cause death or irreparable injuries that would render meat and poultry non-kosher, according to Koves.

Rabbis Koves and Werchow said they believe the kosher slaughter method is no less humane than the methods used in conventional meat production. In addition to the intensive process of sharpening and inspecting the knives, the shochet is trained to make the cut in a single smooth motion, severing the animal’s nerves and draining the blood from the brain in seconds.

“Whatever you think about ... whether kosher slaughter is better for the animal than regular slaughter, you are basically putting animal rights ahead of human rights,” Koves said. “If people are going to ban our rights to have kosher food, that means that they are limiting our human rights. And this, especially in a place like Europe, brings very bad memories to us.”