The Big 6 foodborne pathogens are Norovirus, Hepatitis A, Shigella, Shiga toxin-producing E. coli (STEC), Salmonella Typhi, and nontyphoidal Salmonella. The FDA Food Code singles them out because they spread easily through infected food workers, take very few organisms to cause illness, and often lead to hospitalization.1U.S. Food and Drug Administration. FDA Food Code 2022 A diagnosis in any employee — or certain symptoms, even without a diagnosis — triggers mandatory reporting to the local regulator and either exclusion or restriction from work until specific reinstatement criteria are met.
The Food Code itself is a model, not a federal law. States and localities adopt it (with variations) to regulate restaurants, grocery stores, and institutional kitchens.2U.S. Food and Drug Administration. FDA Food Code The rules below reflect the 2022 edition; check your jurisdiction for any local wrinkles.
The Six Pathogens at a Glance
Norovirus
The most common cause of sudden, widespread foodborne outbreaks. Symptoms start 12 to 48 hours after exposure and usually pass within one to three days.3Centers for Disease Control and Prevention. About Norovirus As few as 10 to 100 viral particles can cause infection, so a single sick employee can sicken an entire dining room.
Hepatitis A
Targets the liver. The average incubation period is 28 days, with a range of 15 to 50.4Centers for Disease Control and Prevention. Clinical Overview of Hepatitis A That long window is what makes it so dangerous in food service: an infected worker can handle food for weeks before feeling sick.
Salmonella Typhi
Exists only in human hosts. About 2 to 5% of recovered patients become chronic carriers, shedding bacteria in stool long after they feel well. The Food Code treats it more aggressively than other Salmonella strains for that reason.
Nontyphoidal Salmonella
Originates mostly from animal sources — poultry, eggs, and produce exposed to animal waste. It survives on dry surfaces for weeks, making cross-contamination a persistent kitchen concern.
Shigella
As few as 10 to 100 organisms can cause shigellosis, with severe cramping, diarrhea, and fever. Person-to-person spread through the fecal-oral route is the primary concern in food establishments.
Shiga Toxin-Producing E. Coli (STEC)
Includes the O157:H7 strain. Produces toxins that can damage the intestinal wall and, in serious cases, cause kidney failure. The infectious dose is thought to be under 100 bacteria.
What Employees Must Report
The Food Code puts reporting duties on food employees and on conditional employees (people who have accepted a job offer but haven’t started).1U.S. Food and Drug Administration. FDA Food Code 2022 They must tell the Person in Charge (PIC) about any of the following symptoms: diarrhea, vomiting, jaundice, sore throat with fever, or an uncovered infected wound on the hand or wrist. They must also report a diagnosis of any Big 6 pathogen, even without symptoms.5Regulations.gov. Employee Health and Personal Hygiene Handbook (FDA Form 1-B)
Household exposure counts too. If an employee lives with someone diagnosed with a Big 6 pathogen, or with someone who works at or attends a facility with a confirmed outbreak, the employee has to report that. The window depends on the pathogen: 48 hours from last exposure for norovirus, 3 days for STEC or Shigella, 14 days for Salmonella Typhi, and 30 days for Hepatitis A.1U.S. Food and Drug Administration. FDA Food Code 2022
What the Manager Does Next
When the PIC learns of a Big 6 diagnosis or sees jaundice in an employee, the Food Code requires the PIC to contact the local regulatory authority immediately.1U.S. Food and Drug Administration. FDA Food Code 2022 There is no next-business-day allowance. From that point the regulator decides whether a broader outbreak investigation is warranted.
None of this works without a paper trail set up in advance. The FDA’s Form 1-B is a written agreement that food and conditional employees sign, acknowledging their duty to report symptoms, diagnoses, and exposures. It warns that failure to comply “could lead to action by the food establishment or the food regulatory authority that may jeopardize my employment and may involve legal action.”5Regulations.gov. Employee Health and Personal Hygiene Handbook (FDA Form 1-B) Get it signed during onboarding. The PIC also has to be able to demonstrate knowledge of employee health obligations and the exclusion process to inspectors at any routine inspection.
Exclusion vs. Restriction
The Food Code draws a sharp line between two responses, and the distinction matters for compliance.
- Exclusion: the employee cannot work in or even enter the establishment as an employee.
- Restriction: the employee may work but cannot touch exposed food, clean equipment, utensils, linens, or unwrapped single-use items. Cashiering or bussing is allowed; food prep is not.
Which one applies depends on the pathogen, whether the employee has symptoms, and whether the establishment serves a highly susceptible population.1U.S. Food and Drug Administration. FDA Food Code 2022
Anyone actively vomiting or with diarrhea is excluded, regardless of cause. The PIC doesn’t wait for a lab result. Hepatitis A and Salmonella Typhi always mean exclusion, even when the employee has no gastrointestinal symptoms, because of their severity and transmission patterns.1U.S. Food and Drug Administration. FDA Food Code 2022
For the other four — Norovirus, Shigella, STEC, and nontyphoidal Salmonella — an asymptomatic employee who tests positive is excluded if the establishment serves a highly susceptible population, and only restricted if it doesn’t. Nontyphoidal Salmonella is the one exception: an asymptomatic carrier is restricted rather than excluded, regardless of the population served.1U.S. Food and Drug Administration. FDA Food Code 2022
Highly Susceptible Populations Change the Math
A highly susceptible population is people more likely to suffer severe consequences from foodborne illness: the immunocompromised, the very young, and the elderly. In practice, that means hospitals, nursing homes, child care centers, adult day care programs, and kidney dialysis centers.
If you manage a kitchen in one of these settings, the margin is narrower. Asymptomatic carriers who would only be restricted at a standard restaurant have to be fully excluded from your establishment. This is the single distinction most likely to trip up a manager who learned the rules in a regular restaurant and moves to an institutional kitchen.
Reinstatement Rules by Pathogen
Reinstatement is not one-size-fits-all. Every pathogen has its own timeline and documentation standard, and every reinstatement requires approval from the local regulatory authority.1U.S. Food and Drug Administration. FDA Food Code 2022
Norovirus
A symptomatic employee can return once the PIC has regulator approval and either the employee produces medical documentation that they are free of infection, or more than 48 hours have passed since symptoms resolved. An employee diagnosed without symptoms can return 48 hours after diagnosis, with regulator approval.
Hepatitis A
If the employee had jaundice, they can return after being jaundiced for more than 7 calendar days. If they had other symptoms, the wait is more than 14 calendar days from onset. Medical documentation that the employee is free of infection also satisfies the requirement. Regulator approval is always needed.
Shigella and STEC
Same path for both. The employee provides medical documentation based on two consecutive negative stool cultures, taken at least 24 hours apart and no earlier than 48 hours after the last dose of antibiotics. An asymptomatic employee can instead wait more than 7 calendar days from diagnosis. Regulator approval is required either way.1U.S. Food and Drug Administration. FDA Food Code 2022
Nontyphoidal Salmonella
Two consecutive negative stool cultures on the same timing rules as Shigella and STEC, or, for an employee who never had symptoms, more than 30 days from diagnosis. The long window reflects how long the bacteria can persist in the gut without obvious illness.
Salmonella Typhi
The strictest standard. The employee must provide written medical documentation from a health practitioner stating they are free of infection, plus regulator approval. There is no time-based alternative — a small share of typhoid patients become chronic carriers, so the only acceptable proof is a medical determination that the infection is gone.
Symptoms That Trigger Action Without a Diagnosis
Focusing only on the six diagnoses misses half the rulebook. The Food Code also requires action on symptoms alone, before any lab result. Vomiting or diarrhea means immediate exclusion, whether the cause turns out to be a Big 6 pathogen or last night’s takeout.1U.S. Food and Drug Administration. FDA Food Code 2022
Jaundice that appeared within the last 7 calendar days triggers exclusion unless the employee provides medical documentation that the jaundice is not caused by Hepatitis A or another fecal-orally transmitted infection. A sore throat with fever triggers exclusion in establishments serving highly susceptible populations and restriction everywhere else. Reinstatement from a sore throat with fever requires medical documentation that the employee has received antibiotic therapy for a strep infection for more than 24 hours, has a negative throat culture, or has been cleared by a health practitioner.1U.S. Food and Drug Administration. FDA Food Code 2022
Train staff to report these symptoms right away, even the minor-seeming ones. A food handler who quietly powers through a bout of diarrhea is the exact scenario the Food Code is built to prevent, and it’s the one that most often shows up in multi-person outbreaks traced back to a single kitchen.