Scientists Develop Patch to Detect When Food’s Gone Bad

Researchers Hanie Yousefi and Thid Didar examine a transparent patch, which can be used in packaging to detect pathogens on food. (McMaster University)

(CN) – Unsure if the bacon that’s been sitting in your refrigerator is still good? A new test can help people determine the critical question of whether food products are safe to eat or must be thrown out.

A team of researchers at McMaster University in Canada has developed a transparent test patch, printed with harmless molecules, which can signal contamination as it occurs. The patch can be incorporated directly into food packaging to evaluate the contents and indicate the presence of harmful pathogens like salmonella and E. coli.

The test, described in a study published Thursday in the journal ACS Nano, has the potential to replace the traditional “best before” date on food products and drinks with a definitive sign that it is time to throw away ground turkey or pour out milk.

“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,” said lead author Hanie Yousefi, a graduate student and research assistant in McMaster’s Faculty of Engineering.

The presence of a pathogen in a food or drink would trigger a signal in the packaging that could be read by a smartphone or other devices. The patch does not affect the contents of the package.

Foodborne pathogens cause roughly 600 million illnesses and 420,000 deaths each year, according to the World Health Organization. Roughly 30 percent of those cases involve children younger than six years old.

The team is naming the new patch “Sentinel Wrap” as a tribute to the McMaster-based Sentinel Bioactive Paper Network, an interdisciplinary research network that developed paper-based detection systems. The network’s research ultimately led to the creation of the patch.

McMaster’s Carlos Filipe, a chemical engineer, and Tohid Didar, a mechanical-biomedical engineer, worked closely together on the new detection project.

The signaling technology was developed in biochemist Yingfu Li’s labs at McMaster.

“He created the key, and we have built a lock and a door to go with it,” said Filipe.

The team says mass producing the patch would be relatively cheap and straightforward, as the DNA molecules that detect food pathogens can be printed onto the test material.

“A food manufacturer could easily incorporate this into its production process,” said Didar, an assistant professor of mechanical engineering and member of the of the McMaster Institute for Infectious Disease Research.

Getting the test to market would require regulatory approval and a commercial partner, the researchers note. They point out that the technology could also be used in other applications, such as wrapping surgical instruments to assure sterility and in bandages to detect if wounds are infected.


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