"I wrote them a check!" said 91-year-old Robert Olsten as he left the store with about $50 worth of Christmas gifts.

Olsten said he'd heard the story on the radio Thursday morning and decided against putting his purchases on his Discover card as he would have.

Victoria Jones took the opposite approach. The 42-year-old Santa Rosa resident chose to put her cart-load of purchases on a credit card instead of her debit card, reasoning it was smarter to let the credit card company bear the risk instead of the hard-earned cash in her checking account.

"I went to swipe my debit card and went, 'Wait a minute!'" Jones said.

She said she knows she shopped at the store during the period in question, and will now keep an eye out for any unusual activity on her account.

As word of the theft spread, banking and credit union officials on the North Coast urged cardholders to monitor their accounts and report any suspicious activity. They assured customers they wouldn't be charged for any unauthorized transactions.

"They really shouldn't panic at this point," said Robin McKenzie, spokeswoman for Redwood Credit Union. "It's important to stay calm and realize they are not responsible for any fraudulent activity. They are covered."

McKenzie said the institution received about 300 calls from its 230,000 members expressing concern. But so far, none have reported losses, she said.

The credit union was not advising people who shopped at Target during the period to apply for new cards.

Brad Hunter, senior vice president of Exchange Bank, said he had not heard of any customers falling victim either. But he said as many as 4,000 of the 50,000 people who had bank debit cards could have shopped at Target during the busy holiday season.

Hunter said an area of concern is Target's store-issued charge card known as the Red Card, which can be tied to checking accounts.

He said bank officials were watching closely to see if the card will add any exposure to bank customers.

But like at other institutions, Exchange Bank card holders will not be liable for any losses associated with the fraud. Any suspicious purchases will be flagged by a computer and capped before exceeding about $400.

"It has the potential to look like the Albertsons breach from earlier this year," Hunter said. "If it comes to that, we will reissue cards to holders who have been through the store in that time frame. If customers have concerns they can call and get a new card."

Hunter said the banking industry is moving toward a new system expected to come on line in 2015 that would make retailers responsible for losses, he said.

Right now, banks are on the hook. Stores like Target face only damage to their reputations, he said.

"It might hurt holiday sales but they won't have to pay for it," Hunter said. "Our bank and other issuers will take the loss."

Target acknowledged the breach a day after news reports surfaced that the store was conducting an investigation. The theft did not affect online purchases, the store said.

Information was stolen from Target brand cards and major credit cards such as Visa and MasterCard.

The store said it immediately informed authorities and financial institutions when it became aware of the breach Dec. 15.

Target advised customers Thursday to check their statements carefully. Those who see suspicious charges on the cards should report it to their credit card companies and call Target at (866) 852-8680.

Cases of identity theft also can be reported to law enforcement or the Federal Trade Commission.

"Target's first priority is preserving the trust of our guests and we have moved swiftly to address this issue, so guests can shop with confidence. We regret any inconvenience this may cause," said Gregg Steinhafel, Target's chairman, president and CEO in a statement.

Unhappy Target customers made angry comments on the company's Facebook page. Some threatened to stop shopping at the store and others complained about not getting through on Target's call center or website.

But customers in Santa Rosa Thursday afternoon didn't seem too worried about the news, and none said their opinion of the popular retailer was affected.

Nicole Lewis, 39, of Bennett Valley, said she just got new credit cards a couple months ago following a breach, and it wasn't much of an inconvenience. She said she'll keep an eye on her account but assumes any suspicious transactions will be flagged and removed.

"My credit card company will notify me," Lewis said.

Target hasn't disclosed exactly how the data breach occurred, but said it has fixed the problem and credit card holders can continue shopping at its stores.

Target is just the latest retailer to be hit with a data breach.

TJX Cos., which runs stores such as T.J. Maxx and Marshalls, had a breach that began in July 2005 that exposed at least 45.7 million credit and debit cards to possible fraud. The breach wasn't detected until December 2006.

In June 2009 TJX agreed to pay $9.75 million in a settlement with multiple states related to the massive data theft but stressed at the time that it firmly believed it did not violate any consumer protection or data security laws.

The Associated Press and Staff Writer Kevin McCallum contributed to this report. You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com.