Angry Shake Shack customers are urging the fast-food chain to cut ties with the controversial company that makes its burger buns

• The family behind Martin's Potato Rolls has donated to Sen. Doug Mastriano, according to Billy Penn.
• Mastriano is known for his Christian nationalist views and his denial of the 2020 election results.

The Shake Shack chain has become synonymous with smashed burgers, crinkle-cut fries, and Martin's Potato Rolls. But the latter has become a cause for concern among customers after local Pennsylvania news site Billy Penn reported that the people behind the bun company have donated thousands of dollars to the front-running Republican candidate for Pennsylvania governor, Sen. Doug Mastriano.

Mastriano is regarded as a far-right Republican and recently received President Trump's backing in the race for governor, according to NBC News. Billy Penn reported that he gained popularity as a Trump-supporting election denier with Christian nationalist beliefs.

Mastriano was also subpoenaed by the congressional committee investigating the January 6 insurrection. NBC News reported that Mastriano used campaign money to charter buses that brought people to the Capitol.

According to Billy Penn, Jim Martin, the former president and current executive chair of Martin's Potato Rolls, gave $110,000 to Mastriano's gubernatorial campaign in 2021 — the largest donation to his campaign to date. He also donated $11,000 in 2020, according to the outlet.

Billy Penn reported that several other members of the Martin family have also donated to Mastriano, including Jim's wife Donna Martin, who gave an "in-kind donation worth a little over $4,000." Julie Martin, Jim's daughter and the social-media manager for Martin's Potato Rolls, gave $2,000 last year, according to the outlet.

Soleil Ho of the San Francisco Chronicle reported that several Bay Area restaurants will stop purchasing Martin's, and Mike Strauss of Mike's BBQ in Philadelphia told Billy Penn that he plans to stop using the rolls at his burger pop-ups. While Strauss told Billy Penn he "stays out of politics," he said he is "disturbed" by this news and that he "would prefer for my money not to support that."

Strauss is just one of several restaurateurs who spoke with Billy Penn about their concerns and their plans to stop using the buns. Mike Strauss did not immediately respond to Insider's request for comment.

Quinnie's, a restaurant and market in Hudson, New York, posted its own photo denouncing the bun company and stating that it will no longer be purchasing them. The eatery also directly called on Shake Shack to join in using other buns.

"Doug Mastriano is an open anti-Semitic, election fraud conspirator, anti-abortion, racist, homophobic who attended the insurrection on Jan 6," the caption read. "We don't want to take part in the support of something we so strongly disagree with."

Quinnie's declined to comment further when reached by Insider.

Joe Rosenthal, a mathematician and food-industry whistleblower, also posted a slideshow on Instagram, which sparked conversation on social media.

"I've been a fan and supported Martin's endlessly over the years on social media, and on my website, but Jim Martin's donation can't be separated from Martin's as a brand, and Martin's can't be separated from the far-right Christian nationalism that Mastriano firmly represents," Rosenthal captioned the photos.

Industry folks and other followers reshared Rosenthal's post and added their own calls for restaurants, individuals, and chains to stop purchasing the buns. (Rosenthal has saved many of the reshares in a highlight reel titled "Martin's" on his Instagram page.)

In two succeeding posts, Rosenthal shared the San Francisco Chronicle's reporting on the company and its close ties to Shake Shack. He called for Danny Meyer (CEO of Union Square Hospitality Group), Randy Garutti (CEO of Shake Shack), and Mark Rosati (culinary director at Shake Shack) to address the controversy and stop the chain's longtime partnership with Martin's as a supplier.

"It sucks," Rosenthal told Insider. "I'm not here because I want to hate on a burger bun company."

Rosenthal told Insider he is a fan of the buns and included them in a gift guide he published on his website last year. The buns have now been removed from his guide with a note about the controversy.

"I like Shake Shack," he continued. "I just want everybody to stop funding a far-right Christian nationalist. It serves to harm so many people that are marginalized. It's scary. It's scary if he wins. If far-right Christian nationalism becomes normalized. That's what this is about."

In a statement to Insider, a representative for Shake Shack said they are engaged in conversation with Martin's.

"Shake Shack has always championed equality, inclusion, and belonging at our company — and we know these values are important to our guests and team members," the statement read. "Shake Shack does not make political donations, nor does the company endorse the political donations of private individuals."

"In regards to the actions of individuals associated with the Martin's company and their personal political donations — those are the choices of those individuals and do not express the values of Shake Shack," it continued. "We continue to be in active conversations with Martin's to express our concern."

On May 17, Martin's posted the above video of an American flag and a Christian nationalism flag on Instagram for primary election day in Pennsylvania. The caption read: "Martin's as a company does not donate to any particular political candidate or party, but we encourage and celebrate the opportunity we all have to vote and share in the election process."

A representative for Martin's echoed the above in a statement provided to Insider and said the company is "aware of the criticisms," adding that it will "continue to focus on the values that have made our company successful — baking quality products, providing excellent service to our customers, and supporting the communities around us."