NEW YORK — The founders of the social-service agency Mazon, after recently announcing wall-to-wall religious support for their High Holy Days anti-hunger appeal, are unhappily eating their words.

This year, for the first time, the Orthodox Union and the Jewish Reconstructionist Federation said they would officially sign on to the campaign.

At the last minute, however, the O.U. pulled out.

Mazon raises money for soup kitchens, food banks and other projects aiding both Jews and non-Jews. The Reform and Conservative movements have been official Mazon supporters for years, distributing the group's materials to their member synagogues at Yom Kippur and Passover, when Mazon runs its two major annual synagogue appeals.

Mazon had even scheduled a photo-op to record the unusual sight of leaders from each of the movements standing united to fight hunger at a time when so much else divides them.

However, the O.U.'s staff member dealing with the project hadn't followed the organization's protocol requiring the board of directors to formally approve the project before making any public announcement.

And when members of the Orthodox Union's board met on Aug. 5, they decided they were not prepared to give the Mazon endeavor a rubber stamp of approval.

The O.U. is considering getting involved with anti-hunger efforts and the board wanted to explore all of its options, said Nathan Diament, director of the O.U.'s Institute of Public Affairs.

"We won't be signed on to this initiative," Diament said of Mazon's High Holiday appeal. But he added that the "conversation is continuing" with Mazon.

Mazon's founders expressed disappointment with the development.

"I thought this was a table at which all four movements could sit down together," said Irving Cramer, Mazon's founding executive director.

"It doesn't make me angry; it makes me heartsick" that the O.U. isn't participating at the moment, he said.

But, he added, "I think great headway has been made that gives us optimism for the future."

When Cramer and longtime social activist and writer Leonard Fein founded Mazon in 1986, they provided $20,000 to projects feeding the hungry.

This year Mazon — Hebrew for "sustenance" — anticipates distributing about $2 million to some 200 of the 450 to 500 projects that requested funding.

Mazon asks Jewish families to contribute to the organization 3 percent of the amount they plan to spend on celebrating their joyous occasions. It also conducts a Passover appeal that this year raised over $400,000 from 9,000 individual contributions.

Mazon's High Holiday appeal last year raised $615,000 from 13,000 contributors who were attending services in 550 different Reform, Conservative and Reconstructionist congregations, said Cramer.

Roughly 30 percent of the money goes to Jewish-run projects, and the rest to groups under Christian and secular auspices.