In 1986, his close friend, Willard Hackerman, who is president and chief executive of Whiting-Turner Contracting Co., offered him a job as a kosher events caterer at the newly constructed Sheraton Inner Harbor Hotel.
"His efforts were praised in The New York Times, and he received the Lifetime Achievement Award from the Academy of Travel and Tourism of Maryland," said a daughter, Ilene Brave of Pikesville.
Mr. Zetlin, who had lived at the 7 Slade Avenue condominiums for more than 40 years, had not retired from the Sheraton Inner Harbor Hotel at his death.
For more than 70 years, he was an active member of Beth Tfiloh Congregation, where he had been president of the congregation and attended services twice a day.
"He was a member of a group of congregants who not only prayed together, but also discreetly looked out for the good and welfare of the sick and financially distressed," his daughter said.
Mrs. Brave said her father led the effort that resulted in two Northwest Baltimore Dunkin' Donuts locations becoming strictly kosher.
He was a past president of the B'nai B'rith Hackerman Lodge.
His wife of 37 years, the former Mildred Savetman, died in 1979. His second wife, of 13 years, the former Bernice Siscovick, died in 1996.
Services were held Wednesday.
Also surviving are another daughter, Linda Isen of Potomac; a stepson, Dr. David Siscovick of Seattle; two stepdaughters, Dr. Harriet Davidson of Boston and Abbye S. Sperber of Durham, N.C.; 12 grandchildren; and 14 great-grandchildren.