A century of matzo tradition is crumbling on the Lower East Side.

Streit's Matzo Factory, which has been baking the kosher unleavened bread since 1915, will put out its last signature pink boxes on Rivington Street this Passover.

But the 100-year-old brand isn't stuck in the past. "When you think of a Jewish mother I hope you think of me," Streit's new spokeswoman and former "Real Housewives of New York City" star Jill Zarin said during a factory tour yesterday.

Inside the 90-year-old building at 148 Rivington St., machines nearly that age cranked out hot, crisp sheets of matzo at the rate of 1,800-plus pounds per hour. But after using much of the same machinery for the past half century, Streit's is in need of an update. Old equipment cannot be repaired or replaced, and the factory's ovens have slowed.

The upgrade will happen outside of Manhattan, as the company is looking for a 100,000-square-foot facility where it can manage both manufacturing and shipping, processes currently split between Rivington Street and New Jersey.

"Emotionally, customers may be sad," co-executive vice president Aaron Gross said of the upcoming move. "But we have a lot of hoops to jump through that a lot of our competition doesn't. This is a competitive business. The fact that we made it here this long is amazing."

Along with the upgraded ovens and the addition of Zarin as a spokeswoman, the company has launched an online store and is planning to post various recipes to a new blog.

The modernizing efforts prove that "it's not the end of an era," said Alan Adler, another Streit's co-executive vice president and cousin to Gross. "We care about this family business. We're just moving; nothing else will change."