Sick workers were behind a plurality of foodborne illness outbreaks and contamination in the U.S., new federal data shows.
In a report published Tuesday afternoon, the Centers for Disease Control and Prevention looked at outbreaks across 25 state and local health departments from 2017 to 2019.
They found that among outbreaks where a contributing factor was identified, four in 10 -- or 41% -- were caused by food contamination from ill or infectious employees.
This included handlers, workers or preparers making either gloved or barehanded contact with food.
"If a food worker stays on the job while sick and does not wash his or her hands carefully after using the toilet, the food worker can spread germs by touching food,' the CDC writes on its website.
Of managers who were interviewed, 91.7% said their restaurant or establishment had policies requiring food workers to notify their manager when they were ill.
However, "often these policies were missing components intended to reduce foodborne illness risk," the CDC said.
For example, 66% of managers said they had a written policy about workers notifying superiors regarding illness.
Only 69.5% specifies symptoms that would lead to restricting or excluding ill workers from working. But just 23% said their policy specified the five symptoms of foodborne illness workers needed to report to their manager including vomiting, diarrhea, jaundice, sore throat with fever and lesions with pus.
The report also found that under half -- 43.6% -- of managers interview said their establishments provided paid sick leave to any workers.
"Contamination of food by ill food workers is a top contributing factor to foodborne outbreaks in retail food establishments; therefore, identifying gaps in these establishments' ill worker policies is important to outbreak prevention," the authors wrote in the report.
"Health departments responsible for ensuring food safety in retail food establishments can use the findings in this report to assess their food safety priorities and guide their outbreak investigations and routine (i.e., preventive) inspections," they continued.
The report also found that 17.6% was caused by contaminated food that was meant to be consumed raw, undercooked or underprocessed.
Another 10.6% of outbreaks were caused by improper or slow cooling of food and 6.6% were caused by either insufficient time, temperature or both during the cooking or heating process.
What's more, when it came to what bacteria or viruses led to the outbreaks, norovirus was the most commonly identified cause at 47%.
Norovirus is a highly contagious virus that is the most common cause of viral gastroenteritis, which is an inflammation of the inside lining of the gastrointestinal tract. In fact, it is the leading cause of foodborne illness in the United States, causing 58% of foodborne illnesses each year, according to the CDC.
This was followed by salmonella -- a bacteria that lives in the intestinal tract of animals -- accounting for 18.6% of outbreaks.