The Associated Press reports on a new use of customer-loyalty-card data by the Centers for Disease Control and Prevention that may raise privacy issues. Note that, in this case, the CDC and grocery stores first asked for customers’ permission to access the data:
As they scrambled recently to trace the source of a salmonella outbreak that has sickened hundreds around the country, investigators from the Centers for Disease Control and Prevention successfully used a new tool for the first time — the shopper cards that millions of Americans swipe every time they buy groceries.
With permission from the patients, investigators followed the trail of grocery purchases to a Rhode Island company that makes salami, then zeroed in on the pepper used to season the meat.
Never before had the CDC successfully mined the mountain of data that supermarket chains compile. […]
Some privacy advocates, though, are troubled.
Longtime shopper-card critic Katherine Albrecht, director of a group called Consumers Against Supermarket Privacy Invasion and Numbering, said she worries that the practice could lead to a switch from a voluntary system to mandatory use of such cards. […]
Several large supermarket chains did not respond to requests for comment on health investigators’ use of shopper cards, but Costco — where Cirimele bought meat that was later recalled — said it provided data to the CDC once customers gave their OK.