Whole Foods shoppers in the Bay Area may have had their credit card information accessed by hackers, according to a warning from the retailer.

The breach affected taprooms and full table-service restaurants in several Bay Area cities. The company first announced the hacking last week but did not reveal at first which cities were affected as they investigated the situation.

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According to Whole Foods, the taprooms and restaurants use a different point-of-sale system than the company’s primary store checkout systems, so payment cards at the regular cash registers were not affected.

A statement issued by Whole Foods said that when it learned of the breach, “the company launched an investigation, obtained the help of a leading cybersecurity forensics firm, contacted law enforcement, and is taking appropriate measures to address the issue.” It also encouraged customers to monitor their credit card statements and report any unauthorized charges to their banks.

Bay Area stores affected by the breach include the tap rooms and restaurants in these stores: