Those cards you swipe at grocery stores — sure, they'll shave some money off your bill and give stores all kinds of info about your food and personal-toiletry preferences — well, now they're a public health tool.
With shoppers' permission, the Centers for Disease Control and Prevention used purchases by people who got sick in a recent Salmonella outbreak to trace the source of contaminated food to salami made in Rhode Island. That allowed them to finger the pepper that was used in the salami.
Here's the Associated Press article about it. It was apparently the first time the CDC ever used such cards to figure out the source of a food poisoning outbreak.
— Rosie Mestel
Photo credit: Karen Tapia-Andersen / Los Angeles Times