Publix has been Florida's favorite grocery chain for decades — but some shoppers are turning their backs on the store after learning it donated more than half a million dollars to gubernatorial candidate Adam Putnam.

A handful of state advocacy groups have gone to social media — Twitter in particular — urging shoppers to "#BoycottPublix" this Memorial Day weekend.

Some people have decided to boycott the store indefinitely, or until it withdraws $670,000 it has given to Putnam, a longtime Republican politician who drew ire after he called himself "a proud NRA sellout" and opposed Florida's new, stricter gun purchasing laws in the wake of the Parkland school shooting.

"Prior to social media, it was much harder to aggregate a bunch of people to take action," said Thomas O'Guinn, a professor of marketing with the University of Wisconsin-Madison. "Consumers are starting to realize the new source of power they have."

@PublixHelps Today my groceries at Target and the local fish market came to $115.54 NOT spent at @Publix, making a total of $224.74 since May 17th.#TweettheReceipt #BoycottPublix #NeverAgain pic.twitter.com/Sur5LEcBYW— Koop (@horassonang) May 21, 2018

@PublixHelps Today my groceries at Target and the local fish market came to $115.54 NOT spent at @Publix, making a total of $224.74 since May 17th.#TweettheReceipt #BoycottPublix #NeverAgain pic.twitter.com/Sur5LEcBYW

David Jenkins, of Tampa, estimates he spends between $500 and $600 on groceries every month at Publix.

"Well, used to spend," he clarified.

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He'd long been impressed by the chain's customer service — which historically has high marks, according to annual reports put out by the American Customer Satisfaction Index.

On Saturday Jenkins did his weekly shopping trip at Winn-Dixie instead, posting the receipt of the trip to Twitter and declaring he wouldn't shop at Publix until it stopped backing Putnam, the current state Commissioner of Agriculture. Jenkins said voting with his wallet was one of the few things he felt he had control over.

As of Monday afternoon, about two dozen people had posted similar photos with "#TweetTheReceipt" to Twitter.

"I'm sure if you went through every corporate chain you could find something you disagree with, but there's a certain point where you draw a line," he said. "This situation — where the amount of money is so substantial and the stakes so high — is the line."

Last week Publix responded to Twitter backlash, posting it considers a number of factors when supporting a candidate and has never given money to the National Rifle Association. In a statement to the Tampa Bay Times, it called Putnam the hometown candidate who is "pro-business."

Publix declined to make any additional comments on Monday.

The Florida groups calling for the boycott this long weekend include First Coast Progressive Women, Indivisible Tallahassee and Ponte Vedra United for Progress.

On Monday, there weren't any obvious signs that droves of shoppers were abandoning the Lakeland-based chain, which ranked No. 1 in customer experience the last two years in the ACSI report. But on the social media, users were sharing a flier in support of this weekend's boycott.

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Maurice Schweitzer, a professor of Management from the University of Pennsylvania, said for any boycott to be successful, protestors have to be consistently motivated over time. Similar boycotts in recent history haven't been overwhelmingly successful, he said, but that doesn't mean they go unnoticed.

"Corporate leaders are very adverse to negative media attention," Schweitzer said. "Publix does a lot to foster good will in the community and create a positive image. So, this campaign has a greater image threat than an economic threat."

Social media posts since the Tampa Bay Times reported the donation amount a week ago has been a back-and-forth battle in what's an already divided state.

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Several tweets of support for Publix have been going out as well — shoppers who say they plan to vote for Putnam in the Republican primary against Rep. Ron DeSantis and will still shop at the store.

Schweitzer said the uproar will likely blow over.

O'Guinn, however, said that the political climate and fervor from activists following the Parkland massacre along with the organization and steady protesting means there's at least a chance boycotters could be successful.

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"In a classically purple state, you've got a good chance of bringing pressure on this grocery chain," O'Guinn said. "If I was Publix, I would want to fall on the right side of history."

Contact Sara DiNatale at sdinatale@tampabay.com. Follow @sara_dinatale.