Health officials are using your key ring to help save lives.
If you get sick, the Department of Health can trace what you've purchased at grocery stores by looking at the history stored on your loyalty card.
It helps you get better and can help thousands from eating the same infected food.
If you have a loyalty card, not only do grocery stores tailor coupons for you, but health officials can use the information of what you buy to help solve food-borne illness outbreaks.
Health officials have recently traced e-coli outbreaks in New York City through this method, and in turn, the people affected were treated the right way, and the infected food was taken off the shelves.
When you go to a grocery store, it's likely the first thing you do when checking out is scanning your loyalty card, and that card can provide health officials with valuable information.
"I think the information can be used in a helpful way," explained Ram Nambiar, Acting Director of Bureau of Epidemiology at the Department of Health.
Nambiar says the information stored on your card can help trace disease outbreaks.
"During a possible food-borne disease outbreak investigation, that can give us a hint of what people have purchased and possibly what they ate, and when they ate it," explained Nambiar.
That information can help the department find the cause of the disease outbreak, and they can more easily treat the sickness and help warn others who may have bought the same food.
“Whenever we're doing an outbreak investigation, we're trying to find out what was the problem and try to make sure that problem, first of all, stops at that time, and make sure that doesn't continue," Nambiar added.
The Pennsylvania Department of Health and Welfare only uses this information a couple of times a year, but when going through thousands of possibilities, this information can be extremely helpful.
"People don't remember exactly what they purchased and what they ate, and sometimes the loyalty cards can help with memory," Nambiar continued.
If multiple people come forward and say they're sick and they have all shopped at the same store, it can be helpful in the investigation.
"We can look at these cards and say 'everyone purchased this item on this date', it helps us," Nambiar told us.
The Department of Health says that this is completely confidential. Before using any of this information, they make sure they have consent from the card owner as well as the grocery store.
They say so far, everyone has been extremely helpful and have given their full support.