The fear of whether a steak or a carton of milk is past its prime may soon be alleviated.
Researchers from McMaster University in Canada have developed a new transparent test patch embedded with molecules that can signal whether contamination has occurred in food, replacing the traditional “best before” date tags commonly used on food and drinks.
The patch, dubbed the “Sentinel Wrap,” can be incorporated directly into food packaging to monitor the contents for harmful pathogens like E. coli and Salmonella. The patch generates a fluorescent signal in the presence of specific target bacterium.
“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,” lead author Hanie Yousefi, a graduate student and research assistant in McMaster’s Faculty of Engineering, said in a statement.
To fabricate the sensor, the researchers covalently attached picoliter-sized microarrays of an E. coli-specific RNA-cleaving fluorogenic DNAzyme probe (RFD-EC1) to a thin, flexible, and transparent cyclo-olefin polymer (COP) film.
If a pathogen were present at a given item, a signal in the packaging is sent to a smartphone or other device alerting the user of the potentially dangerous product. The patch can be mass-produced in a simple and inexpensive manner.
“A food manufacturer could easily incorporate this into its production process,” mechanical-biomedical engineer Tohid Didar, an assistant professor of mechanical engineering and member of the McMaster Institute for Infectious Disease Research, said in a statement.
The patch can detect bacteria while still attached to the food package, eliminating the need to manipulate the sample. The biosensors remain stable for at least the duration of the shelf life of perishable packaged food products.
Similar technology has been used for bandages to indicate if wounds are infected and for wrapping surgical instruments to assure they are sterile.
According to the World Health Organization, foodborne pathogens result in approximately 600 million illnesses and 420,000 deaths per year, with about 30 percent of the cases involving children five years old or younger.
The researchers now plan on seeking out a commercial partner and obtaining regulatory approvals.
The study was published in ACS Nano.
