Still, because of a Georgia law that kosher food meet "Orthodox Hebrew religious rules," the rabbi from the Conservative Jewish movement does not have the authority to certify kosher restaurants.
Georgia is the latest front in the debate over whether kosher laws are kosher after Zimmerman and other rabbis, backed by the American Civil Liberties Union, challenged the law. Similar rules have been struck down in at least two other states, and attorneys say five others could be targeted: Louisiana, Michigan, Missouri, Texas and Wisconsin.
"You can't have the government of the U.S. or the government of the state of Georgia determining which branch of Judaism is authoritative," said Zimmerman.
The rabbi and his allies, all members of the Conservative stream of Judaism, say the law should be overturned because not all Jews are Orthodox - the most traditional interpretation of Jewish teaching. The state, they contend, breaches the First Amendment when it favors one religious group over another.
This clash over kosher has been waged before.
The New Jersey Supreme Court struck down the state's kosher food regulations in 1992, finding they "plainly violate constitutional standards" that call for the separation of church and state. And a federal appeals court struck down similar rules in New York in 2002.
But Georgia's statute didn't become front-and-center until Zimmerman was challenged over certifying a vegetarian restaurant in northeast Atlanta. That frustrated him and other Conservative rabbis who routinely supervise facilities to ensure food is kosher.
"As a rabbi, I'm clearly in breach of the Georgia law any time I try to certify a restaurant, an institution, a catering facility as kosher," said Rabbi Shalom Lewis, a plaintiff in the lawsuit who leads Congregation Etz Chaim in Marietta.
"I don't want to have to choose between abiding by state law and practicing my religion according to my beliefs," Lewis said.
The argument is centered on the complex Jewish dietary laws that have guided observant Jews for centuries.
The main kosher principles - no pork, no mixing meat and milk - cross the streams of Judaism. But different traditions have different requirements for how certain foods are inspected and processed. For instance, rabbis disagree over whether they should consider some gelatin kosher; gelatin, found in candy, desserts, yogurt and other food, is made from animal products.
Orthodox leaders say states like Georgia stick to their regulations because they set a firm standard that relies on centuries of Jewish law and custom.
"The purpose of the law is to protect kosher consumers," said Orthodox Rabbi Reuven Stein, who directs the Atlanta Kashruth Commission. "One of the reasons they chose the Orthodox standard is that it is a standard that everybody agrees on."
He said he sees the legal challenge as a political move that imperils dietary rules that have been in place in Georgia since 1980.
"When you take away protections from people that keep kosher and you're doing it to score political points, you are being anti-religious," Stein said.
But civil rights groups say the state crosses the line when it endorses one set of beliefs over another.
One way to fix the problem is to require that kosher products carry labels that note which group certified them, said Daniel Mach, a litigation director for the ACLU. It's already a common practice for some groups, but he said writing it into the state law can strike a balance between protecting observant Jews and upholding the Constitution.
"We understand the need to respect consumers who want to ensure that items purchased with a kosher designation meet their community's faith. That's fine," he said. "But the state shouldn't be playing favorites when it comes to religion."
Zimmerman, who leads Congregation Beth Shalom in Dunwoody, hopes the legal challenge will allow him to once again serve as a mashgiach, the Hebrew term for someone who certifies food as kosher.
"There are different rabbinic voices within the Jewish community, and the government should not be in the business of deciding which expressions of Judaism are legitimate and authoritative," he said. "If this law is not one that violates the separation of church and state, I don't know what is."