Colorado State Scientists Work to Control Listeria Outbreak

Colorado State University researchers are conducting research and education activities for the prevention of listeriosis outbreaks such the one spreading through Canada. In the last several weeks, foods contaminated with Listeria monocytogenes have resulted in more than 60 illnesses and at least 17 deaths in Canada. More than 190 brands of meats and cheeses have been recalled.

Scientists at Colorado State’s Center for Meat Safety and Quality and the Food Safety Cluster are working with colleagues at four other universities in the United States to better understand and control such outbreaks. John Sofos, professor in the Department of Animal Sciences at Colorado State and director of the Center for Meat Safety and Quality, is the project coordinator.

"The scientists involved in this project are available to provide guidance to the industry and consumers relative to the various aspects of listeriosis and listeria control," Sofos said.

Listeria monocytogenes is a deadly pathogen transmitted through consumption of contaminated food. The organism, found widely in the environment, can grow at refrigerator-level temperatures. Usually, the pathogen causes human infection through consumption of refrigerated, ready-to-eat foods such as deli meats, soft raw-milk cheeses and seafood salads. The time between consumption of a contaminated food product and onset of illness may be as long as 70 days.

Although the incidence of listeriosis is relatively low, when it strikes, it can be severe. Twenty percent to 30 percent of those who are diagnosed with listeriosis die, with the elderly and fetuses of pregnant women being the most at risk.

Symptoms of the listeriosis infection may include high fever, severe headache, neck stiffness and nausea. Severely infected adults may develop meningitis or other severe complications. Foods contaminated with the pathogen may appear normal with no signs of smell or spoilage.  

Sofos, along with researchers from Cornell University, University of Nebraska, Ohio State University and Kansas State University, have developed various research, education and outreach components that are designed to reduce the risk of listeria transmission by intervening at the processing, food service and consumer level.

"As project director, I will answer questions or I will direct questions to those members of the consortium most qualified to address them," Sofos said.

The project is funded by the National Integrated Food Safety Initiative of the Cooperative State Research, Education and Extension Service of the U.S. Department of Agriculture.