Novel patch can detect food contamination in real time

Scientists have developed a transparent patch that can detect if food has gone bad, by monitoring the presence of harmful pathogens in real time.

The patch can be incorporated directly into food packaging, and signal E coli and Salmonella contamination as it happens.

The technology, published in the journal ACS Nano, has the potential to replace the traditional "best before" date on food and drinks alike with a definitive indication that it is time to throw away that roast or pour out that 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 Hanie Yousefi, a graduate student at McMaster University in Canada.

If a pathogen is present in the food or drink inside the package, it would trigger a signal in the packaging that could be read by a smartphone or other simple device. The test itself does not affect the contents of the package.

According to the World Health Organization (WHO), food-borne pathogens result in approximately 600 million illnesses and 420,000 deaths per year.

About 30 per cent of those cases involve children five years old and younger.

The material, named "Sentinel Wrap" would be cheap and easy to mass produce, as the DNA molecules that detect food pathogens can be printed onto the test material, researchers said.

"A food manufacturer could easily incorporate this into its production process,"said Tohid Didar, an assistant professor at McMaster.

Getting the invention to market would need a commercial partner and regulatory approvals, researchers said.

They point out that the same technology could also be used in other applications, such as bandages to indicate if wounds are infected, or for wrapping surgical instruments to assure they are sterile.