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.
“That sends chills down my spine,” she said.
Some state and local health agencies have used shopper cards to trace cases of food poisoning. Before this outbreak, the CDC had tried it a few times, too, but without success, Behravesh said.
Some supermarkets have also used shopper-card information to notify customers by letter or automated telephone call that a product they bought has been recalled.
Health authorities trying to trace the source of a food-poisoning outbreak typically ask victims what they bought and what they ate. But without receipts or other hard evidence, they often find themselves at the mercy of people's memories.
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.
“In this instance, we actually worked very closely with the CDC,” said Christine Summers, the Issaquah, Wash., chain's director of food safety. “They ask, 'Did this member purchase products A, B or C in this time frame?' and we tell them, 'Yes, they did' or 'No, they didn't.'“
Supermarkets generally will supply information to health authorities if customers consent, said Jill Hollingsworth, vice president of food safety at the Food Marketing Institute, a trade group for groceries in the U.S.
Bruce Chassy, a food safety professor at the University of Illinois at Urbana-Champaign, said he is intrigued by the new means of tracing food-poisoning cases. He noted it can be extremely difficult to get to the bottom of outbreaks caused by relatively minor ingredients.
“Cantaloupes and eggs are easy,” he said. “The fact that it's only an ingredient in products in other things, that makes it really hard to track.”
J. Kathryn MacDonald, an epidemiologist with the Washington state Health Department who worked on the salmonella outbreak, such some advocates' privacy fears are unfounded.
“This is not being used as a tool for open-ended trawling through many records hoping to find something,” MacDonald said. “The records are treated with the same level of confidentiality as would medical records.”
What do you think? Post a comment on this article and share your opinion with other readers. Submit your comments to Modern Healthcare Online at [email protected]. Please be sure to include your hometown and state, along with your organization and title.