Amazon.com Inc’s (AMZN.O) Whole Foods Market on Thursday said payment card information has been stolen from taprooms, restaurants and other venues located within some of its stores.

The upscale grocer, which Amazon recently purchased for $13.7 billion, said it uses a different point-of-sale system for its roughly 450 U.S. stores. That system was not involved in the data hack, the company said.

Whole Foods said the Amazon.com systems do not connect to the affected systems at Whole Foods and that Amazon.com transactions also were not involved.

More than 40 Whole Foods stores sell beer on tap. The company did not immediately say how many restaurants are in its stores.

Whole Foods said it has launched an investigation into the hack, obtained the help of a leading cyber security forensics firm, contacted law enforcement, and is taking appropriate measures to address the issue.