Real-time detection of pathogenic contaminants in food and on equipment

Real-time detection of foodborne pathogens will play a critical role in minimising the occurrence and spread of disease and give food processors confidence in their sanitation systems and quality assurance.

Traditional methods of Salmonella detection tend to be slow, while disease spread can be frighteningly fast. Foodborne illnesses spread easily and can be a difficult-to-control problem. In the US, the Centers for Disease Control and Prevention has estimated that 48 million people experience ‘food poisoning’ each year, with 128,000 being hospitalised and 3000 dying.

If foodborne disease pathogens are detected quickly the spread of contamination can be minimised and contained.

Recognising the need for a real-time biosensing system to detect pathogenic bacteria, such as Salmonella, a team of Auburn University researchers came up with a novel design, which they describe in the American Institute of Physics’ Journal of Applied Physics.

What sets this biosensing system apart from traditional detection methods is a design that involves using 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’s 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,” he explained.

“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,” Chai says.

By stark contrast, the 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.”

The researchers have filed a patent for their magnetoelastic biosensing system.

The paper, Design of a surface-scanning coil detector for direct bacteria detection on food surfaces using a magnetoelastic biosensor, authored by Yating Chai et al, appears in the American Institute of Physics' Journal of Applied Physics.