40% of US foodborne restaurant outbreaks traced to sick workers

Sick barista

Estradaanton / iStock

Forty percent of US foodborne illness outbreaks at restaurants and other food-serving establishments from 2017 to 2019 were related to a sick worker, according to a study published today in Morbidity and Mortality Weekly Report.

Researchers from the Centers for Disease Control and Prevention (CDC) led the study, which involved collecting environmental health data during the investigation of 800 foodborne illness outbreaks at 875 retail food establishments reported to the National Outbreak Reporting System (NORS) by 25 state and local health departments from 2017 to 2019.

Most jurisdictions' food-safety regulations are based on the US Food and Drug Administration (FDA) Food Code, recommendations designed to reduce foodborne illness in retail establishments.

The study used environmental health data, which are usually only minimally reported to NORS, from the National Environmental Assessment Reporting System (NEARS). Since it was established in 2014, NEARS has received environmental health data on foodborne illness outbreaks from 29 health departments.

Norovirus, Salmonella most common causes

Among the 800 outbreaks, 27.0% occurred in 2017, 38.3% in 2018, and 34.8% in 2019. Of these outbreaks, 90.6% involved one establishment, and 9.4% involved multiple establishments. A total of 3.5% were multistate outbreaks. The most common pathogens, which were involved in 69.4% of the outbreaks with a confirmed or suspected agent, were norovirus and Salmonella, making up 47.0% and 18.6% of outbreaks, respectively.

Most identified agents were viral (48.1%) and bacterial (46.8%), followed by parasitic (2.3%) and toxic or chemical (2.5%) causes. A total of 819 contributing factors were identified.

Of the 500 outbreaks with an identified contributing factor (eg, bare-handed contact with ready-to-eat food), 85.2% had at least one contamination factor, 25.8% had at least one proliferation factor (conditions allowed pathogens in food to grow), and 14.2% had at least one survival factor (pathogens survived processes designed to kill or reduce their numbers).

Of the contributing factors identified in 62.5% of outbreaks, about 40% had at least one reported factor related to food adulteration by an ill or infectious worker. When investigators interviewed an establishment manager in 679 outbreaks (84.9%), they found that 91.7% said they had a policy requiring food workers to notify them when they were ill, with 66.0% reporting that their policies were written.

A total of 23.0% of managers said their policy listed all five symptoms in the FDA Food Code requiring manager notification (vomiting, diarrhea, jaundice, sore throat with fever, and lesion with pus). The vast majority of managers (85.5%) said they had a policy limiting tasks or excluding ill employees from working, and 62.4% said the policy was written.

Only 17.8% of managers said their policy listed the same five symptoms that would also require restricting or excluding employees from working—not just notify managers—and 16.1% had policies addressing all four components of the FDA Food Code pertaining to ill or infectious employees.

These components include a policy requiring workers to notify a manager when they are ill, a list of all five symptoms mandating workers to notify a manager, a policy that limits or excludes employees from working, and a policy listing all five symptoms requiring limiting or excluding employees from work. Less than half (43.6%) of managers said their establishments offered paid sick leave to at least one food worker.

Workplace policies often incomplete

A multilayered approach to reducing foodborne illness outbreaks "not only includes adoption and enforcement of comprehensive written ill worker policies but also enhances training, management plans to continue operations when a worker is absent (e.g., on-call staffing), and adoption of a food safety culture where absenteeism due to illness is not penalized," the study authors wrote.

The researchers said their results are consistent with findings from other national outbreak datasets and highlight the role of ill workers in foodborne illness outbreaks. "Although a majority of managers reported their establishment had an ill worker policy, often these policies were missing components intended to reduce foodborne illness risk," they wrote. "The content and enforcement of existing policies might need to be re-examined and refined."

Restaurants can prevent viral foodborne illness outbreaks by mandating proper hand hygiene and excluding ill or infectious employees from working, the researchers said.

Although a majority of managers reported their establishment had an ill worker policy, often these policies were missing components intended to reduce foodborne illness risk.

"NEARS data can help identify gaps in food safety policies and practices, particularly those concerning ill workers," they said. "Future analyses of stratified data linking specific outbreak agents and foods with outbreak contributing factors can help guide the development of effective prevention approaches by describing how establishments' characteristics and food safety policies and practices relate to foodborne illness outbreaks."

This week's top reads