JERSEY CITY, N.J. — Except for a poster of grains from around the world, the office of Yaakov Horowitz at Manischewitz looks like a typical rabbi's study.

Heavy books with Hebrew script are stacked on the shelves, portraits of other rabbis adorn the walls, and Horowitz displays a shofar, or ram's horn, that he blows on his company's production floor before the Jewish High Holy Days.

As chief rabbi at the kosher food company Manischewitz, the world leader in matzoh production, Horowitz is the matzoh maven. Grain used to produce matzoh is a big part of his life.

"It's not just the most important kosher food," said the 51-year-old Horowitz. "It is also the most important Jewish food and the last link to Jewish heritage. I feel the responsibility very profoundly."

He oversees the company's annual production of 75.6 million sheets of matzoh, the unleavened bread eaten by Jews worldwide during the eight-day Passover holiday and the centerpiece of the seder.

The first seder, or Passover dinner, begins Monday night as Jews commemorate the biblical account of their ancestors' liberation from slavery in ancient Egypt. They eat matzoh on Passover to remember the hasty departure, which didn't leave enough time for bread to rise.

The fourth-generation Hasidic rabbi has traveled around the world to consult about matzoh production at factories in Mexico, Moscow, Kiev, England and Israel and is now embarking on a new task: designing the first new matzoh ovens for Manischewitz in nearly 70 years.

The company is moving operations to Newark, leaving behind its historic ovens in Jersey City, where mass-produced matzoh was revolutionized.

Manischewitz's parent company, R.A.B. Food Group of Secaucus, N.J., recently acquired other kosher food companies and is consolidating production of both wet food such as soup and gefilte fish, and dry goods such as cake mixes, crackers and matzoh.

The new $10 million oven will improve the company's matzoh production because daily cleaning during the Passover season can be done in less than a quarter of the time, Horowitz said.

And when the company makes its once-a-year conversion to Passover goods, it'll take less than a week instead of a month, said Jeremy Fingerman, president and chief executive officer of the privately held R.A.B., which acquired the Manischewitz brand in 1998.

Matzoh is still the most important product Manischewitz produces, said Horowitz, who dons a yarmulke, hair net and another net to protect his bushy salt-and-pepper beard when he's on a factory floor.

Rabbi Dov Behr Manischewitz founded his company in Cincinnati in 1888 to produce matzoh. By 1914, the company registered more than 50 patents for matzoh baking and, six years later, it had created a machine that could produce matzoh on a massive scale — 1.25 million sheets a day.

In 1939, the company moved its matzoh operations to Jersey City, which closed its plant this month.

The introduction of a machine is still debatable among some Orthodox Jews, said Horowitz, whose e-mail user name is "matzohmail."

Matzohs were historically made by hand and sold by synagogues as a source of income from the 1700s until the latter part of the 19th century.

"Since the 1850s, people involved in machine matzoh have been forever trying to improve on the design, to be able to break it down better to clean it more efficiently and quicker," Horowitz said.

According to the Jewish laws of kashrut, matzoh must be baked in 18 minutes or less, with ovens at intense heat, between 650 degrees and 800 degrees. Matzoh cannot mix with leavened products. The Newark factory will have its own air ventilation system for the Passover production area.

"Matzoh production is a little bit like maritime law," Horowitz said. "It's an independent specialty. It's a different part of the kosher law book."

During the season for Passover products, between seven and 11 mashgiachim, or kosher supervisors, work for the rabbi to inspect the matzoh products.

One is stationed in Pennsylvania for six months to oversee the Passover production of the flour as it is grown, milled and trucked to New Jersey in 40,000-pound tankers. Between five and eight tankers will deliver the flour for 20 straight weeks. The company also manufactures matzoh under the Horowitz-Margareten (no relation) and Goodman's labels.

"Matzoh is always watched, from the time of grinding," said Horowitz, who speaks English, Hebrew and Yiddish. "Again, this is ancient law."

Interpreting these ancient laws is part of Horowitz's job. But Fingerman said he does a lot more for the entire company, which consists of other kosher food brands including Rokeach, Mother's, Mrs. Adler's and Mishpacha.

"The rabbi has a pretty good eye from a manufacturing perspective," he said.

Horowitz previously worked with other accounts, companies such as the J.M. Smucker Co. and Nestle USA, to supervise and coordinate their kosher food programs for the Orthodox Union as he now does full time for Manischewitz. The nonprofit organization inspects 6,000 plants in 80 countries worldwide and certifies their products as kosher.