Norovirus causes most food illnesses, CDC says



It is a simple thing, but it amazes Randy Wishard how often food service workers overlook good handwashing practices.

“They know it,” said Wishard, the environmental health manager for Richmond County Health Department. “They’ve been taught it. They just get real comfortable” and forget.

That lack of hand hygiene and food service workers who show up for work sick are likely reasons a common and highly contagious virus is the source for many food illness outbreaks, the Centers of Disease Control and Prevention said Tuesday. Norovirus, a virus most often associated with outbreaks on cruise ships, is actually the culprit, said CDC Director Thoams Frieden.

“In fact, norovirus is the leading identified cause of outbreaks from contaminated food in the U.S.,” he said.

About 20 million people a year are sickened by norovirus and between 2009 and 2012 the CDC identified 1,008 foodborne outbreaks of the virus, including 14 in Georgia and seven in South Carolina, according to the CDC’s Vital Signs report.

Nearly two-thirds of cases were in restaurants and 17 percent were from catering or banquet halls. Of the 520 cases where the contamination factor could be identified, 70 percent were attributed to infected food service workers, the report noted.

“Some food service workers understandably fear losing their job and also leaving co-workers short-staffed if they don’t go to work when they are sick,” Frieden said.

The food service industry could do more to help prevent that, such as offering paid sick leave and having on-call staffing, he said.

Part of the problem is the nature of the virus itself, Frieden said. The virus can stay infectious at freezing temperatures and remain so until heated above 140 degrees, and it can be viable on surfaces up to two weeks, the report noted. It takes as little as 18 viral particles to infect another person and an infected person can shed up to 10 billion viral particles in a single gram of feces, the report said.

“The bottom line is norovirus is one tough bug,” Frieden said. “You only need a miniscule dose, a tiny number of virus particles, to become infected.”

While they might be taught good handwashing techniques, food service workers can run into problems when transitioning between areas of restaurants, such as taking out the garbage or going to the restroom, said Wishard, whose department averages about five calls a week from people who think they were sickened eating somewhere.

“They are required to wash their hands in the restroom, but before they enter that food service prep area they are required to wash their hands again,” Wishard said, which might be where the problem starts.

Trained managers and a re-emphasis on proper techniques will help, Frieden said.

“We do know how to stop norovirus from contaminating our food,” he said. “Because the virus is so infectious, it is important that there is scrupulous handwashing. We know how to stop it; we just need to do it. Everyone should be able to go out to eat without worrying about whether their food is safe.”