Amazon has introduced the Amazon One payment system to a Whole Foods store in Seattle as a trial.  The technology is distinct from Just Walk Out that allows shoppers to bypass checkout lines. 

The palm-scanning technology involves linking an electronic image with a credit card to establish a link.  Thereafter the credit card is charged each time the palm is scanned. If successful it is intended to expand the Amazon One scanning system to other Whole Foods stores. 

There are obvious concerns over the technology relating to confidentiality given that a commercial entity will possess biometric data.