Federal authorities have awarded research funding to scientists studying ways to control noroviruses — highly contagious and hard-to-kill viruses.

The U.S. Department of Agriculture is giving $25 million to North Carolina university researchers to study human noroviruses so scientists can better understand and develop effective control measures to lower the number of norovirus-related foodborne outbreaks.

Human noroviruses cause more than 21 million illnesses a year and human noroviruses are said to be responsible for more than half of all foodborne disease outbreaks.

Lee-Ann Jaykus, a professor in food microbiology in the department of food, bioprocessing and nutrition sciences with North Carolina State University, Raleigh, said the research should provide a variety of perspectives through integration with other scientists in other disciplines. She said the research is important as effective norovirus detection methods haven’t been developed.

“Fresh produce is a significant cause of noroviruses,” Jaykus said. “We don’t really know where the contamination is coming from. Is it coming from the preharvest environment during irrigation or from the hands of individuals engaged in harvesting fresh produce? Or from wash water or when people are preparing salads at home or at the retail level?”

Jaykus said noroviruses remain resistant to most food processes as well as manufacturer-recommended disinfectant applications.

She said the research, which also involves scientists at Clemson University, Baylor College of Medicine, Emory University and the National Foundation for the Centers for Disease Control and Prevention, includes public outreach through extension and other publicity.