Real-time Salmonella sensing

Foodborne illnesses spread quickly and rapid detection can play a critical role in halting the spread of contamination. Traditional detection methods, however, tend to be painfully slow - particularly when your brand’s reputation is at stake.

Recognising the need for a real-time biosensing system to detect pathogenic bacteria such as Salmonella, a team of researchers from Auburn University in the US has come up with a novel design, outlined in the American Institute of Physics’ Journal of Applied Physics.

The biosensing system incorporates a magnetoelastic biosensor - a low-cost, wireless acoustic wave sensor platform - combined with a surface-scanning coil detector. The biosensors are coated with a bacteria-specific recognition layer containing particles of ‘phage’, a virus that naturally recognises bacteria, so that it is capable of detecting specific types of pathogenic bacteria.

Traditional technologies required the sensor to be inside a coil to measure the sensor’s signals, said Yating Chai, a doctoral student in Auburn University’s materials engineering program.

“The key to our discovery is that measurement of biosensors can now be made ‘outside the coil’ by using a specially designed microfabricated reading device,” Chai said.

“In the past, if we were trying to detect whether or not a watermelon was contaminated with Salmonella on the outside of its surface, the sensors would be placed on the watermelon and then passed through a large coil surrounding it to read the sensors.”

By contrast, Auburn’s new biosensing system is a handheld device that can be passed over food to determine if its surface is contaminated.

“Now, tests can be carried out in agricultural fields or processing plants in real time - enabling both the food and processing plant equipment and all surfaces to be tested for contamination,” said Chai.

The researchers have filed a patent for the system.