Researchers develop tray that alerts when food is contaminated

Researchers have developed a new packaging tray that signals when food, whether cooked or uncooked, is contaminated. 

The tray can also identify dangerous pathogens present in raw food packaged in most supermarkets or farms worldwide. 

The technology will enable producers, retailers and consumers to tell in real-time whether the contents of a sealed food package are contaminated without having to open it. 

This will prevent exposure to contamination while reducing exposure to diseases caused by consuming contaminated food. 

The tray, shaped like a shallow boat, is lined with a food-safe reagent that allows a built-in sensor to detect and signal the presence of salmonella and other pathogens. This technology can be adopted by any country to test for other common food-borne contaminants such as E. coli and listeria. 

The findings, published in the journal Advanced Materials, revealed that the "Lab-in-a-Package" is capable of sampling, concentrating and detecting target pathogens within closed food packaging without intervention. 

The findings revealed that the packaging tray displayed the highest levels of fluid localisation and fluid transfer compared to a traditional food packaging tray. 

The sides of the tray direct juices to a sensor embedded in a window at the bottom. Users can scan the underside of the sealed package with a cellphone and know immediately whether the food is contaminated without additional lab work.  The efficacy of the developed solution was also confirmed via application-specific testing, which involved contaminating food samples, gloves, surfaces, and knives to better simulate real-world conditions. 

"This system consists of a newly designed packaging tray and reagent-infused membrane that can be universally paired with diverse pathogen sensors. The inclined food packaging tray maximizes fluid localization onto the sensing interface, while the membrane acts as a reagent-immobilizing matrix and an antifouling barrier for the sensor," the study conducted by researchers at McMaster University in Canada, says.  The package-based sensors also measure other conditions such as humidity.  The technology is verified using a newly discovered Salmonella-responsive nucleic acid probe. This probe enables hands-free detection of colony-forming units (CFU) targeting pathogens in packaged whole chicken. 

 The technology has immense application for a variety of food samples beyond chicken, including the packaging trays used for other meat and seafood products and the plastic containers used for produce. 

 It “remains effective when contamination is introduced with tools and surfaces, ensuring widespread efficacy. Its real-world solution uses a hand-held fluorescence scanner with smartphone connectivity," the report states. 

It adds: “With food production shifting away from traditional farm-to-table approaches to efficient multistep supply chains, the incidence of food contamination has increased. Accurate detection within unprocessed, packaged food products without user manipulation is needed. 

The lead researcher, Dr Akansha Prasad, indicated that all materials used in the study were selected from the Indirect Food Substances provisions, ensuring regulatory viability through the generally recognised as a safe designation from the US Food and Drug Administration. 

"We're hoping this technology will save lives, money and prevent food wastage. This is something that can benefit everyone,” says the researcher, adding that “we wanted to develop simple and inexpensive technologies to prevent and detect food contamination”. 

 Dr Shadman Khan, co-lead author of the paper, says, “We wanted to develop a system that was reliable, quick, affordable and easy to use since there is a lot at stake with food safety.” 

Further, the researchers indicated that protecting consumers from contaminated foods will create significant healthcare savings. 

About 600 million cases of foodborne illness occur globally every year, largely due to the consumption of pathogen-contaminated food products. 

"It's really just a matter of time before technology like this becomes common all over the world," said Tohid Didar, an associate professor of mechanical and biomedical engineering who holds the Canada Research Chair in Nano-biomaterials. 

 "Now that we've shown that one kind of food package can reveal contamination without even being opened, we can adapt this to other forms of packaging for other types of foods,” he advised. 

 Professor Yingfu Li, of biochemistry and biomedical sciences, McMaster’s Chair of Chemical Engineering, who supervised the research, says that being able to combine packaging and salmonella detection in one system is already very promising. 

 "It also shows that we can add sensing probes for other food-borne pathogens to the same system so that the package will check for all of them at once. That's our next step, and we're already working on it. 

 He adds: “The findings will allow public health authorities, producers and retailers to trace and isolate contamination quickly, reducing potentially serious infections and cutting back significantly on food waste by identifying precisely which lots of food need to be recalled and destroyed, compared to broad recalls that end up wasting unspoiled foods. 

 The research, which is part of McMaster's Global Nexus School for Pandemic Prevention and Response, involved 11 scientists from the fields of biomedical, mechanical, and chemical engineering, medicine and biochemistry. 

 Toyota Tsusho Canada Inc., an indirect subsidiary of Toyota Tsusho Corporation in Japan, supported the research. 

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