(Reuters) – Amazon.com Inc’s (AMZN.O) Whole Foods Market said on Friday it had replaced affected point-of-sale systems at venues located within some stores where payment card information had been stolen.

The upscale grocer last month disclosed card information had been stolen from taprooms, restaurants and other venues located within some of its stores.

Whole Foods, which Amazon recently purchased for $13.7 billion, said transactions on Amazon.com had not been impacted.

The investigation found unauthorized software was present on the point-of-sale systems at certain venues, the company said.