Why Restaurants Have Outbreaks: Sick Workers and Missing Policies, 2017–2019

Every year, state and local health departments report hundreds of foodborne outbreaks to CDC, and most start in retail food establishments — restaurants, caterers and other places that prepare, serve or sell food directly to the public. Health departments send the epidemiology and lab findings to the National Outbreak Reporting System (NORS), but little about what went wrong in the kitchen. That is the job of the National Environmental Assessment Reporting System (NEARS), launched by CDC in 2014 and still the only source of data on the environments where these outbreaks happen.

Erin D. Moritz and colleagues at CDC summarized NEARS reports for 2017–2019.

The data

Twenty-five state and local health departments reported: Alaska; California; Connecticut; Delaware; Fairfax County, Virginia; Georgia; Harris County, Texas; Indiana; Iowa; Jefferson County, Colorado; Kansas City, Missouri; Maricopa County, Arizona; Massachusetts; Michigan; Minnesota; New York; New York City; North Carolina; Oregon; Rhode Island; South Carolina; the Southern Nevada Health District; Tennessee; Washington; and Wisconsin.

An outbreak is two or more people with a similar illness from eating a common food. Investigators recorded the cause, contributing factors, the business's characteristics and its policies, largely through interviews with managers.

The outbreaks

• 800 outbreaks linked to 875 establishments: 216 in 2017, 306 in 2018 and 278 in 2019.
• 725 (90.6%) involved one establishment and 75 more than one; 28 (3.5%) crossed state lines.
• Investigators interviewed a manager in 679 outbreaks (84.9%).
• Most businesses were independently owned (65.2%) and served 300 or fewer meals a day (60.7%), though one served up to 8,500.

The causes

A cause was identified in 555 outbreaks (69.4%), confirmed by lab in 71.7% of those.

Viruses caused 48.1% of identified outbreaks, bacteria 46.8%, toxins or chemicals 2.5% and parasites 2.3%. Source: CDC, MMWR.

How they happened

At least one contributing factor was found in 500 outbreaks (62.5%), 819 factors in all. Contamination figured in 85.2% of those, germs growing in food (proliferation) in 25.8%, and germs surviving a step meant to kill them in 14.2%.

The five most common factors were all contamination:

Gloved-hand contact by an infectious worker followed at 10.6%. Top growth factors were improper or slow cooling and cold holding in broken refrigerators; the top survival factor was undercooking. In all, about 40% of outbreaks with an identified factor involved an ill or infectious worker.

The policy gap

The FDA Food Code — the model most jurisdictions base their rules on — says workers should tell a manager when they have any of five symptoms (vomiting, diarrhea, jaundice, sore throat with fever, a lesion with pus) and be restricted or kept from work when they do. Adopting it is voluntary. Among 725 managers interviewed:

Vomiting and diarrhea were the symptoms most often named, yet about a third of policies left them out.

What would help

• Comprehensive, written, enforced policies. Written policies are linked to smaller norovirus outbreaks than spoken ones, and cleaning and glove policies to smaller outbreaks too. But writing a policy is not enough: FDA modeling shows high compliance with exclusion policies sharply cuts predicted illnesses, and states that legally require excluding ill workers have lower norovirus outbreak rates. Policies checked during inspections tend to be enforced.
• Paid sick leave. Workers cite lost pay and social pressure as reasons to work sick. Expanded paid sick leave in one restaurant chain reduced working while ill, and supportive sick-leave rules are linked to lower foodborne illness rates. A layered approach — training, on-call staffing plans, and a culture that doesn't punish sick days — may be needed.
• Basic food handling. Hand hygiene and keeping sick workers out protect against viral outbreaks. Against bacteria, the Food Code's guidance on preventing cross-contamination and on cooking, reheating, holding and cooling food matters, especially since most outbreak kitchens used complex processes with riskier steps.

Limitations

Health departments report to NEARS voluntarily and investigate in different ways, not every outbreak is found or investigated, managers answered from memory and may have overstated good practices, and the data predate the COVID-19 pandemic, which changed some restaurant practices.

Sources

Based on Moritz ED, Ebrahim-Zadeh SD, Wittry B, et al., "Foodborne Illness Outbreaks at Retail Food Establishments — National Environmental Assessment Reporting System, 25 State and Local Health Departments, 2017–2019," MMWR Surveillance Summaries, Centers for Disease Control and Prevention; a work of the United States government in the public domain.