Five new Listeria species found; may improve tests

Cornell researchers have discovered five new species of Listeria – including one named for Cornell – that provide new insights that could lead to better ways to detect soil bacteria in food.

To date, of the 10 previously known species of Listeria, only two are pathogenic to humans; Listeria monocytogenes is the main cause of Listeriosis, which causes illness in listeriahundreds – and death in nearly 250 – people each year in the United States through infected deli meats, seafood and produce.

The new study, published online March 5 in the International Journal of Systematic and Evolutionary Microbiology, suggests that all five new species are benign.

The research was part of a larger study led by researchers at Colorado State University and Cornell to examine the distribution of such foodborne pathogens as Listeria, E. coli and Salmonella in agricultural and natural environments. Samples were taken from fields, soil, ponds and streams in New York, Colorado and Florida.

“Doing studies on natural diversity in produce fields helps us develop better and more precise tests to make food safer,” said Martin Wiedmann, Cornell professor of food science and the paper’s senior author.