The Big Six Foodborne Pathogens: What Food Managers Must Know
The Big Six are the six pathogens the FDA singles out as most likely to be spread by sick food employees: norovirus, hepatitis A virus, Salmonella Typhi, Shigella spp., Shiga toxin-producing E. coli (STEC), and nontyphoidal Salmonella. If you manage a kitchen, you need to know them by name, because they decide when an employee must report an illness, when you must send someone home, and when that person can come back.
This guide explains each pathogen, how it reaches food, what your employees must tell you, and how exclusion and restriction work in practice.
TL;DR
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The Big Six are norovirus, hepatitis A, Salmonella Typhi, Shigella, STEC, and nontyphoidal Salmonella, as listed in the FDA Employee Health and Personal Hygiene Handbook.
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They share traits that make a sick worker dangerous: low infectious doses, and high numbers shed in feces.
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Employees must tell the person in charge about vomiting, diarrhea, jaundice, sore throat with fever, infected wounds, a Big Six diagnosis, or exposure to one.
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Return-to-work rules depend on symptoms, diagnosis, and who you serve, and your state or local health code is what you must follow.
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Food Protection Managers are expected to know all of this, and you can earn the certification online.
Table of Contents
What the Big Six are and why they matter
The FDA’s handbook identifies the Big Six as norovirus, hepatitis A virus, Salmonella Typhi, Shigella spp., STEC, and nontyphoidal Salmonella. Three are bacteria with a typhoid-or-not split in the Salmonella group, one is a bacterium that produces a toxin (STEC), and two are viruses.
Why these six and not the hundreds of other foodborne germs? FDA explains that they have low infectious doses, infect the gastrointestinal system after ingestion, and are shed in feces in high numbers. That combination means an infected food employee can transmit them even when handwashing is practiced. A few particles on a hand or a glove can be enough to start an outbreak, and a single infected worker touches a lot of food in a shift.
That is the reason health codes treat these six differently from, say, a worker with a common cold. Your rules for reporting, restriction, and exclusion are built around them.
| Pathogen | Type | Group |
|---|---|---|
| Norovirus | Virus | Big Six |
| Hepatitis A virus | Virus | Big Six |
| Salmonella Typhi | Bacterium | Big Six |
| Nontyphoidal Salmonella | Bacterium | Big Six |
| Shigella spp. | Bacterium | Big Six |
| STEC (Shiga toxin-producing E. coli) | Bacterium | Big Six |
The six, one at a time
Norovirus
Norovirus is the one most kitchens will actually meet. CDC explains that it can contaminate food through feces or vomit on hands, contaminated surfaces, aerosolized vomit droplets, or contaminated growing and harvesting environments, and that food workers are a major source in restaurant outbreaks.
The pattern in outbreak data is telling. CDC reported that most foodborne norovirus contamination happens during preparation, with infected food workers and bare-hand contact with ready-to-eat food frequently implicated. CDC’s infection-control guidance adds that norovirus spreads so efficiently because of its very low infectious dose, persistence in the environment, and vomiting aerosols.
For a deeper look at prevention, see our guide to how norovirus spreads in foodservice and how to stop it.
Hepatitis A virus
Hepatitis A is a liver infection, and what makes it tricky for managers is the delay. CDC says symptoms can include abdominal pain, nausea or vomiting, diarrhea, fatigue, fever, dark urine or clay-colored stools, loss of appetite, joint pain, and jaundice. They may appear 2 weeks to 6 months after exposure, and many infected people have no symptoms at all.
That is why jaundice, the yellowing of the skin or eyes, is one of the symptoms your employees must report immediately. An infected person can be handling food long before anyone suspects anything.
Salmonella Typhi and nontyphoidal Salmonella
The FDA list includes two separate Salmonella entries. Salmonella Typhi is the strain behind typhoid fever, and nontyphoidal Salmonella covers the far more common strains most people think of when they hear “salmonella.” Both are on the list, and both trigger reporting duties. Raw poultry, eggs, and produce are familiar sources, and the way they reach ready-to-eat food is almost always the same: cross-contamination or an infected handler. Our article on raw versus ready-to-eat cross-contamination walks through the kitchen habits that prevent it.
Shigella spp.
Shigella causes shigellosis. It is spread through the fecal-oral route, which is why handwashing after restroom use and strict glove and utensil practice matter so much. FDA notes that proper handwashing reduces fecal-oral spread and that avoiding bare-hand contact helps protect ready-to-eat food. A worker who has been diagnosed with shigellosis falls under the exclusion rules described below.
Shiga toxin-producing E. coli (STEC)
STEC is the E. coli group that produces Shiga toxin, and it includes the well-known O157:H7 strain. Beef, leafy greens, and other produce have all been linked to STEC illness, but for a manager the point is simple: a diagnosed STEC infection in an employee means exclusion until the rules for your jurisdiction allow a return.
How the Big Six get into food
Food employees can pass pathogens to consumers through contaminated food. In practice, the routes are few:
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Hands. Feces or vomit on hands, then onto food or food-contact surfaces.
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Bare-hand contact. Handling salads, sandwiches, garnishes, bread, and other ready-to-eat items without a barrier.
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Surfaces and equipment. Contaminated counters, cutting boards, and utensils that move germs from one item to another.
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Vomiting incidents. Aerosolized droplets can settle on food and surfaces nearby.
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The source itself. Contaminated produce or shellfish can arrive already carrying a pathogen.
The Indiana Department of Health notes that onset can range from 1 hour to 28 days, depending on the illness. This wide range is a practical problem: when a customer gets sick, the meal that caused it may not be the last one they ate, and you may not know an employee was infectious until well after the fact.
Good handwashing is the first line of defense, and we cover technique in our handwashing guide for food service kitchens. Handwashing alone is not enough, though. Because these pathogens are shed in such high numbers, the surest control is keeping an infected worker away from food in the first place.
What employees must tell you
Employees and conditional employees (new hires who have been offered a job but have not started) must tell the person in charge about:
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Vomiting
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Diarrhea
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Jaundice
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Sore throat with fever
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Infected wounds or boils
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Exposure to a Big Six pathogen
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A diagnosis of a foodborne illness
This list comes from the FDA handbook, which adds that the manager then decides on the applicable restriction or exclusion.
Notice what that means for you. The employee reports, and you decide. You cannot make that call well unless you know the rules, and your staff will not report if they fear losing a shift’s pay. A written illness policy, plus a culture where staying home is treated as responsible rather than weak, is the practical fix. A Big Six illness policy should be a one-page document everyone signs at hire and sees on the wall.
One more point: reporting is not a one-time conversation. People get sick mid-shift, and exposure happens outside work, such as a sick child at home or a family member diagnosed with norovirus. Train staff to speak up in both situations.
Exclusion and restriction: what they mean
The two terms are not interchangeable.
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Exclusion means the employee cannot work in the establishment at all.
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Restriction means the employee can work, but not around exposed food, clean equipment, utensils, linens, or unwrapped single-use items. Think of a prep-free assignment such as cleaning dining areas or doing paperwork.
The FDA handbook says employees with vomiting or diarrhea should stop work, and that jaundiced employees should stop work. It also says employees with a sore throat and fever in establishments serving highly susceptible populations must stop work until a health practitioner clears them.
CDC research summarizing the FDA Food Code says that in places serving highly susceptible populations, employees with a sore throat and fever, or diagnoses of norovirus, hepatitis A, Shigella, STEC, or Salmonella Typhi, should be excluded. Highly susceptible populations include young children, older adults in care settings, and people with weakened immune systems. If you run a child care kitchen, a senior living facility, or a hospital cafeteria, you are in the strictest category.
The payoff for getting this right is large. CDC states that removing sick food workers from operations can prevent customers from becoming ill and reduce foodborne illness outbreaks.
When can an employee come back?
Return depends on the symptoms, the diagnosis, whether the person is still shedding the pathogen, the type of establishment, and the code that applies to you. The general anchors from the FDA handbook:
| Situation | General FDA guidance |
|---|---|
| Vomiting or diarrhea | Wait at least 24 hours after symptoms end |
| Jaundice | Health practitioner clearance; local health department clearance if it lasts more than 7 days |
| Sore throat with fever (highly susceptible population) | Stay out until a health practitioner clears the employee |
| Some diagnosed Big Six illnesses | May require medical documentation or regulatory approval |
Treat this table as a starting point, not a final answer. A diagnosed case may require more than a symptom-free day, and the person in charge should keep a written record of every decision.
Your state or county sets the actual rule
The FDA Food Code is a model code, not a law. FDA directs operators to follow the state, local, tribal, or territorial health code that applies to their location.
Adoption is uneven. In a CDC assessment of 51 jurisdictions for the 2017 Food Code provisions, 40 required exclusion for vomiting or diarrhea until at least 24 hours after symptoms stopped, while adoption of other provisions was less uniform. So a policy copied from a franchise in another state may be too lax, or simply wrong, where you operate.
If you want state-specific context, we maintain pages for California, Arizona, New York, and Colorado. Always confirm details with your local health department, since that office has the final word on inspections and exclusions.
Beyond the Big Six: other hazards you still manage
The Big Six are the pathogens that drive employee health policy, not the only hazards in your kitchen. Other bacteria, toxins, chemicals, and allergens all belong in your food safety plan. Allergens deserve particular attention because the consequences land on a single customer immediately. Rules differ by country, and the EU, for example, names 14 allergens that must be flagged, as a guide on EU allergens to check on takeout explains. In the United States, the rules are different, so build your allergen training around the requirements that apply where you operate.
For symptoms and prevention beyond the Big Six, our article on spotting and stopping food poisoning is a useful companion.
A practical Big Six checklist for managers
Use this as a working list for your own operation:
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Write the policy. Spell out the reportable symptoms and diagnoses, and who the person in charge is on every shift.
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Get signatures at hire. Have every employee, including conditional employees, acknowledge the reporting duty.
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Remove bare-hand contact with ready-to-eat food. Stock gloves, tongs, deli tissue, and utensils where they are needed.
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Make handwashing easy. Sinks accessible, stocked, and used.
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Plan for vomiting incidents. Have a cleanup kit and written procedure, and keep customers and staff away from the area.
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Document decisions. Record who reported what, what you decided, and when the person returned.
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Know your highly susceptible customers. If you serve them, you are under the strictest exclusion rules.
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Check your local code every year. Adoption of the Food Code changes over time.
Our perspective: knowledge is the control
We train food service professionals every day, and the pattern we see is consistent: operations rarely fail because nobody cares. They fail because the person in charge did not know which symptoms trigger which action. The Big Six framework is useful precisely because it is short. Six names, a handful of reportable symptoms, and a clear decision between restriction and exclusion.
That is why our Food Protection Manager course places employee health at the forefront rather than treating it as an afterthought. Our Food Protection Manager Certification program is ANSI ANAB-CFP nationally accredited and state-approved. Our courses are designed to be self-paced so busy chefs or owners can fit studying around their shift schedules. Practice quizzes let you test your knowledge on key topics before the exam, including which illnesses require exclusion and the proper steps a manager must take when an employee reports symptoms.
Our advice to any manager: do not wait for an outbreak to learn this. Build the habit of asking about symptoms at the start of every shift, make it safe for staff to say they are sick, and keep your reference material within reach. A kitchen that does this has taken the single biggest step against the Big Six.
A great convenience…I have a busy schedule and I never know when I can take time. Course was thorough and had tons of information. Price was great and the on-line proctored test was simple. Thanks for everything.— Barbara E. (Restaurant General Manager
Get certified in the Big Six and beyond
If your jurisdiction requires a certified person in charge, or you simply want to know your decisions will hold up at inspection, our online Certified Food Protection Manager course is $115 and covers employee health, cross-contamination, and the rest of the core food safety content. The proctored CFPM exam is $99 and is taken online with no scheduling required, and the course and exam together are $149.
For line cooks and other staff, the Food Handler course is $29.99, and the Allergy Awareness training is $20. Managers building a broader system can also look at our HACCP Manager Certificate at $249. Check with your local health department first to confirm which certificate your area accepts.
FAQ
What are the Big Six pathogens?
They are norovirus, hepatitis A virus, Salmonella Typhi, Shigella spp., Shiga toxin-producing E. coli (STEC), and nontyphoidal Salmonella. The FDA identifies them as the pathogens most associated with transmission by infected food employees. Your employee health policy should be built around them.
Do the Big Six rules apply in every state?
Not identically. The FDA Food Code is a model, and each state, local, tribal, or territorial government decides how much of it to adopt. Follow the code that applies to your location, and confirm details with your local health department.
How long does an employee need to stay home after vomiting or diarrhea?
FDA guidance says employees should wait at least 24 hours after vomiting or diarrhea ends. Some diagnosed illnesses require more than that, including medical documentation or regulatory approval, so ask your health department when a diagnosis is involved.
How long after exposure do symptoms appear?
It depends on the illness. The Indiana Department of Health notes onset can range from 1 hour to 28 days. For hepatitis A, CDC says symptoms may appear 2 weeks to 6 months after exposure, and many infected people have no symptoms.
Is handwashing enough to stop the Big Six?
No. Handwashing and avoiding bare-hand contact matter, but FDA notes these pathogens are shed in such high numbers that transmission can occur even when handwashing is practiced. Excluding or restricting sick employees is the stronger control.
Sources
Recommended
We strive to keep all program details and requirements as accurate and current as possible. However, regulations may vary by location. For the most reliable and up-to-date information, please confirm requirements directly with your local state or jurisdiction.
