Tiny Patch Can Help Detect Contaminated Foods

sentinel wrap patch
Researchers Hanie Yousefi and Thid Didar examine a transparent patch that can be used in packaging to detect pathogens on food. McMaster University

To eat that old chicken salad or not to eat that old chicken salad ... that is the question (especially when you're broke and hungry). If you've ever stood in front of an open fridge, weighing the pros and cons of eating questionable leftovers, perhaps you've lamented, infomercial-style: "There has to be a better way!" Well now there is. Science!

Researchers at McMaster University in Hamilton, Ontario, have developed a product that has the potential to tip consumers off to a food's contamination status and the presence of harmful pathogens like E. coli and salmonella. The product — a small transparent patch printed with harmless molecules — could actually be incorporated directly into food packaging and replace that old-school (and less-than-helpful) expiration date, according to a report published in the April 6 edition of the journal ACS Nano.


"In the future, if you go to a store and you want to be sure the meat you're buying is safe at any point before you use it, you'll have a much more reliable way than the expiration date," the report's lead author, Hanie Yousefi, a graduate student and research assistant in McMaster's Faculty of Engineering, said in a press statement.

So how exactly does the mighty patch, known as "Sentinel Wrap" work? If it's integrated into standard packaging, any harmful agent like a bacterium or virus that's present in the food or beverage will "show up" when scanned by another device, like a smartphone.

The innovation could have a much bigger impact than just taking the guesswork out of dinner: According to the World Health Organization, foodborne pathogens cause approximately 600 million illnesses and 420,000 deaths every year, and about 30 percent of those cases involve children 5 years old and younger.

But while mass producing Sentinel Wrap could be cheap and easy, according to the researchers, actually getting the invention to market would require a commercial partner and regulatory approvals. Beyond the world of food, the researchers say their technology could be applied to other products like bandages to indicate if a wound is infected, or surgical instrument wrapping to ensure tools are sterile.