Food workers who showed up while sick or contagious were linked to about 40% of restaurant food poisoning outbreaks with a known cause between 2017 and 2019, federal health officials said Tuesday.

Norovirus and salmonella, germs that can cause severe illness, were the most common cause in the 800 outbreaks studied, which encompassed 875 restaurants.

Investigators with the Centers for Disease Control and Prevention called for better enforcement of policies like hand washing and keeping sick workers off the job.

Although 85% of restaurants said they had policies restricting staff from working while sick, only about 16% of the policies were detailed enough to require workers to notify managers and to stay home if they had symptoms.

About 44% of managers told the CDC their restaurants provided paid sick leave to workers.
Mitzi Baum, the chief executive of STOP Foodborne Illness, a nonprofit advocacy group, said it can be hard for consumers to know when sick workers might be on the job, but there are some signs to look for: “Is your server sniffing? Are they sneezing? How are they handling the utensils?”