New sensor detects serious food-borne bacteria on site

Electron micrograph of a flagellated Listeria monocytogenes bacterium, an infectious agent...

Electron micrograph of a flagellated Listeria monocytogenes bacterium




According to the CDC, around 48 million people in the US get sick, 128,000 are hospitalized, and 3,000 die as a result of foodborne illnesses every year.

One of the main culprits is listeriosis (or listeria), which is responsible for approximately 1,600 of these illnesses and 260 deaths. Now researchers at the University of Southampton are trialling a device designed to detect the most common cause of listeriosis directly on food preparation surfaces, without the need to send samples away for laboratory testing.

Listeriosos is usually caused by the Listeria monocytogenes bacterium, resulting in symptoms including fever, vomiting and diarrhea. Untreated, illness can spread to other areas of the body and may lead to more severe complications, such as meningitis. Passed on from foods such as milk, cheese, vegetables, fish, and meat, L. monocytogenes is particularly dangerous for those with weakened immune systems, as well as pregnant women, newborn babies, and the elderly.

To develop a device to detect this potentially deadly bacteria, the Biolisme project – a consortium of six partner organizations from four different countries – was formed. The project developed a sensor capable of gathering and detecting L. monocytogenes directly on food industry surfaces, as both single-cells and biofilms (groups of microorganisms whose cells clump together on surfaces).

The sensor is contained in a device that uses compressed air and water to firstly isolate the cells from the surface being tested, and then move them into contact with a specifically-prepared antibody for detection. If L. monocytogenes is present, the antibody will fluoresce, and this florescence will be detected by a camera specially designed for the device.

Current bacteria detection techniques rely on laboratory testing, which can take days to return results. And, they do not discriminate between harmful live cells and harmless dead cells, thereby possibly returning false readings. The new device is designed to overcome these problems, with the ability to accumulate and detect the pathogen on site within three to four hours.

“The scientific research we have carried out at the University of Southampton has been used by our Biolisme project partners to develop a device which will have major implications for the food industry,” said Dr Gião. “By making the process simpler we hope that testing will be conducted more frequently, thereby reducing the chance of infected food having to be recalled or making its way to the consumer.”

The sensor prototype stage has been completed in France and on-site trials are currently being performed on the device. Once these are completed, the team plans to move onto demonstrations in food processing plants in the near future.

Source: The University of Southampton-complied by Colin Jeffrey-Gizmag, 2014