Food poisoning: Biosensor rapidly detects trace amounts of listeria

Video: Texas A&M AgriLife

A new biosensor now under development at Texas A&M University can rapidly detect the presence of listeria contamination, the nation’s third-leading cause of death from food poisoning.

Carmen Gomes, an assistant professor of biological and agricultural engineering in the College of Agriculture and Life Sciences, is collaborating with a researcher at the University of Florida on the project, which has received funding from the National Science Foundation.

“We hope to soon be able to detect levels as low as one bacteria in a 25-gram sample of material – about one ounce,” Gomes said.

Listeria was chosen as the first target pathogen because it can survive at freezing temperatures. “It can grow under refrigeration, but it will grow rapidly when it is warmed up as its optimum growth temperature ranges from 30 to 37 degrees C. — 86 to 98 degrees F.,” Gomes said. “This makes it a particular problem for foods that are often not cooked, like leafy vegetables, fruits and soft cheeses that are stored under refrigeration.”

It was just this kind of contamination that resulted in a recent outbreak of listeria poisoning in four U.S. states, leading to a massive recall of ice cream products by Texas-based Blue Bell Creameries.

The current method of detecting listeria contamination requires several days for highly trained technicians to complete, she said.  Gomes’ biosensor is still in the prototype stage of development. The eventual product will be a hand-held device that will require little training to use. The technology may also be adapted to detect other food pathogens, Gomes said.