In an effort to improve food safety and reduce the risk of eating spoiled meat, Concordia researchers have designed a new technology that identifies the presence of the toxin putrescine in beef.

Putrescine is responsible for the noxious odors of putrefying meats. If consumed in large doses, putrescine can cause headaches, vomiting, diarrhea and heart palpitations. 

According to the researchers, their newspaper-based synthetic biosensor is inexpensive, reliable, and consumer-friendly.

Lead author Alaa Selim, who is working on her Ph.D. at the University of Saskatchewan’s Vaccine and Infectious Disease Organization says, “Making a rapid, easy-to-use biosensor for people to check the quality of the food they are eating is empowering. We wanted to make a device that anyone could use, that is disposable and contain no toxic materials.”

Their research, titled “A Synthetic Biosensor for Detecting Putrescine in Beef Samples,” was published in the journal Applied Bio Materials. Selim’s co-authors include her former Ph.D. student colleagues at the Shih Microfluidics Lab and Steve Shih, associate professor of electrical and computer engineering.

“We believe our work is a first step toward using sensors in the meat preparation industry,” says Shih. “In addition, we believe this type of sensing can be used for other fields like an environmental sampling of heavy metal contamination and cancer and disease diagnostics.”

Research methods
The technique behind the sensor relies on cell-free protein synthesis, which produces a protein using the biological machinery of a cell without actually using the living cell. 

Researchers added putrescine to the cell-free system that was producing the repressor in a solution and placed it on a paper device to visually see the presence of putrescine under UV light. After an hour, the researchers found that the biosensor was detecting the presence of putrescine; after four hours, they were confident their readings were highly accurate.

Next, they tested actual meat samples. Beef kept in a freezer, in a refrigerator, and at room temperature were compared to see how much putrescine accumulated over the span of several days. 

Results
The samples from the freezer and refrigerator had very low levels of putrescine, while the ones kept at room temperature showed quite high levels. The levels were high enough to sicken anyone who might eat it.

Salim says she wants everyone to be able to use this technology, “whether it’s a college student, a busy mom, or people working in the restaurant industry.”

The full paper can be found here.