Food Safety

12 Common Foodborne Illnesses and Protecting Your Customers From Them

Posted by
Trust20 Contributors • 13 minute read

The old saying goes, “You are what you eat.” That saying couldn’t be any more accurate than when it relates to foodborne illnesses, but the reality is that nobody likes a case of food poisoning.

Keeping your customers healthy should be a top priority whether you’re a chef, server, or line cook. But with so many different types of bacteria and viruses floating around, that’s easier said than done.

From nausea-inducing norovirus to salmonella’s sneaky stomach ache, we’ll break down the most common foodborne illnesses in this post so you can keep everybody happy, healthy–and well-fed.

What is a Foodborne Illness?

What is the #1 Leading Cause of Foodborne Illness Outbreaks at Restaurants?

Most Common Foodborne Illnesses: 11 Other Pathogens to Watch Out For

How to Protect Yourself and Your Customers From Foodborne Illnesses

What to Do if There’s a Foodborne Illness Outbreak

The Takeaway

What is a Foodborne Illness?

A foodborne illness is any illness caused by consuming contaminated food or beverages. There are more than 250 foodborne diseases, some more common than others.

A foodborne illness can manifest with a variety of different symptoms and can be caused by all kinds of factors. It might be that the food wasn’t stored properly or cooked to the correct temperature. Maybe one of the ingredients was spoiled. Perhaps the food was contaminated before it even got to the kitchen.

Foodborne illnesses can lead to issues such as nausea, vomiting, fever, and diarrhea. In some cases, they can even be life-threatening, particularly for those with weakened immune systems (like older adults or those who are immunocompromised in some other way).

Long story short–foodborne illnesses are dangerous and must be treated as such. Around 128,000 people are hospitalized each year in the United States due to foodborne illnesses, and sadly, many of these cases originate in restaurants and other foodservice establishments (not in our own personal kitchens).1,2

Keep reading to learn more about preventing this from becoming an issue in your establishment.

What is the #1 Leading Cause of Foodborne Illness Outbreaks at Restaurants?

Norovirus is the leading cause of foodborne illness outbreaks at restaurants. It’s a highly contagious virus that can cause severe diarrhea, vomiting, and stomach pain. It's spread through contaminated food, surfaces, and even person-to-person contact.

The Centers for Disease Control and Prevention (CDC) estimates that norovirus is responsible for 58% of all foodborne illness outbreaks in the United States. Why is it so common in restaurants? It’s spread easily through contaminated food, water, or surfaces, and it takes only a small amount of the virus to make someone sick. It’s highly contagious and spreads like wildfire from person to person.

Along with Salmonella, Toxoplasma, and Listeria–three other foodborne illnesses we’ll discuss in this post–norovirus is responsible for causing the most deaths.3

You can take plenty of measures as a foodservice professional to prevent norovirus outbreaks. Proper handwashing, especially after using the restroom or handling raw foods, is one of the most effective ways to reduce the spread of norovirus.4

Most Common Foodborne Illnesses: 11 Other Pathogens to Watch Out For

While norovirus is the most common foodborne illness you need to worry about, it’s certainly not the only one.5 The good news is that most of these can be prevented in the same way you’d prevent norovirus–by washing your hands, sanitizing regularly, and preventing cross-contamination.

Nevertheless, it’s essential to be aware of these culprits so you can do everything in your power to keep them off the menu–and off your mind.6 Here’s what to watch out for. 

1. E. Coli

E. Coli is a type of bacteria found in the intestines of animals and humans. While many types of E. Coli are harmless, certain strains can cause serious illness and even death.7

It spreads through contaminated food or water, particularly if it comes into contact with animal feces. That can happen during food production, harvesting, processing, or serving.

Now, let's talk about symptoms. The most common symptoms include severe stomach cramps, diarrhea (which may be bloody), and vomiting. While most healthy adults will recover within a week, young children and older adults can experience life-threatening complications.

Prevention is key here. Foodservice professionals can take measures such as thoroughly washing hands, separating raw meat from other foods, and cooking food to a safe temperature. It's also important to carefully clean all produce and sanitize surfaces where you prepare food.

The impact of E. Coli can be devastating. Not only can it lead to severe illness and long-term health problems, but it can also cause recalls and damage to a restaurant's reputation.

2. Salmonella

Salmonella is a type of bacteria that can make its way into various types of food, including meats, eggs, and even fruits and vegetables. When ingested, it can cause a wide range of symptoms, including fever, stomach cramps, nausea, vomiting, and diarrhea. In severe cases, it can even lead to hospitalization or even death.

So, how does one contract Salmonella? There are a few different ways. Handling raw food without properly washing your hands is one way to spread this disease to other surfaces and contaminate other foods.

Cross-contamination can occur if you use the same cutting board or utensils on raw meat and other foods without cleaning them in between. Sometimes, food can be contaminated even before it makes its way to your kitchen, whether it's due to poor handling practices during distribution or at the farm level.

Of course, the best way to prevent Salmonella is through proper food safety measures. That includes washing your hands frequently, washing fruits and vegetables thoroughly, properly storing and cooking meats to their appropriate internal temperatures, and avoiding cross-contamination.

Some simple kitchen tips, such as using separate cutting boards for raw meat and other foods, can also go a long way in preventing the spread of Salmonella.

3. Campylobacter

This bacterium causes food poisoning and can lead to severe diarrhea, abdominal pain, and fever. In some cases, it can even lead to more severe health complications like Guillain-Barré syndrome.8

So, what are the common causes of Campylobacter? This bacterium is found in raw or undercooked meat and poultry products, unpasteurized milk, and contaminated water. It's important to cook meat and poultry to the proper temperature and always to practice good hygiene when handling food products.

Prevention, again, is key when it comes to Campylobacter. Ensure you cook all meat and poultry products properly, wash your hands regularly (especially after handling raw meat), and only consume pasteurized milk and water from a safe source.

4. Hepatitis A 

Hepatitis A is a viral infection that affects the liver. The virus is primarily transmitted through contaminated food and water and can cause symptoms such as fever, fatigue, nausea, vomiting, and abdominal pain.

Though it can be transmitted in many other ways, one of the leading causes of Hepatitis A in the food service industry is poor hand hygiene and food handling practices, particularly when preparing foods that are eaten raw. That can include not washing hands thoroughly after using the bathroom, using contaminated utensils or surfaces, or not adequately storing or cooking food.

The good news is that you can prevent Hepatitis A with proper hygiene and vaccination. All foodservice professionals should be trained to follow proper hand washing and sanitizing techniques and ensure that all food is stored, handled, and cooked correctly.

The impact of Hepatitis A can be significant, as outbreaks can close down businesses and lead to a loss of revenue. Not only that, but infected individuals may require medical attention and be unable to work for some time, leading to further complications.

5. Listeria

You can find Listeria in soil, water, and even certain animals, such as cows and poultry. It can also be present on produce that has been contaminated, as well as on processed meats and dairy products. For example, you often hear about listeria outbreaks on products like deli meat.

So, what are the symptoms if someone becomes infected with Listeria? The most common symptoms are fever, muscle aches, and gastrointestinal issues such as nausea and diarrhea.

However, it can also lead to more severe complications such as meningitis and sepsis, particularly in vulnerable groups such as pregnant women, older adults, and those with weakened immune systems.

Prevention is key when it comes to Listeria. The proper storage and handling of ready-to-eat foods is essential to preventing the growth of Listeria. Always refrigerate them at or below 40°F and follow recommended cooking and heating temperatures. Be sure to wash all produce before preparing it, too. 

6. Clostridium Perfringens

Clostridium perfringens is another common bacteria that can wreak havoc on our customers’ meals if not handled properly. It thrives in environments with low oxygen, making it a prime culprit for improperly stored or reheated foods. That means that keeping food at the right temperature is crucial in preventing the growth of this harmful pathogen.

Clostridium Perfringens can cause a range of uncomfortable symptoms such as abdominal pain, diarrhea, nausea, and vomiting. Symptoms typically appear anywhere from six to 24 hours after consuming contaminated food but can last several days.

When it comes to prevention, there are several measures we can take to keep our meals safe. Properly cooking and reheating food to the recommended temperatures is a big one, along with ensuring that food is stored at the right temperature and for the right length of time.

7. Staphylococcus aureus

Staphylococcus aureus is a type of bacteria found in the nose and on the skin of humans. It can be transmitted to food through improper handling or poor hygiene practices. When food is contaminated with Staphylococcus aureus, it can cause food poisoning symptoms like vomiting, diarrhea, and stomach cramps.

The good news is that there are ways to prevent Staphylococcus aureus from contaminating your food. Again, many of these are the same sentiments you’ll see echoed above, such as:

  • Practicing good hygiene, such as washing your hands and keeping your work area clean.

  • Cooking food thoroughly to kill any bacteria that may be present.

  • Keeping food at safe temperatures–below 40 degrees Fahrenheit for cold foods and above 140 degrees Fahrenheit for hot foods–prevents bacteria growth.

8. Toxoplasma gondii

Toxoplasma gondii is a parasitic infection that can affect both humans and animals, including livestock and poultry. The leading cause of this infection is ingesting food or water contaminated with the parasite or through contact with infected animals.

The symptoms of Toxoplasma gondii can vary from mild flu-like symptoms to severe neurological implications, including seizures and mental disorders. Pregnant women and individuals with weakened immune systems are at a higher risk of developing severe health complications.

Again, prevention of Toxoplasma gondii infection is crucial, and foodservice professionals should all implement proper hygiene practices when handling and preparing food. That includes washing hands thoroughly, avoiding cross-contamination, and cooking meat products to the recommended temperature.

9. Shigella 

Shigella is a type of bacteria that can easily spread through contaminated food or water, causing a nasty illness known as shigellosis.

So, what are the causes? Shigella thrives in conditions where hygiene isn't up to par. That means improperly washed hands, cross-contamination, and unsanitary food preparation areas are all possible breeding grounds for the bacteria.

The symptoms of Shigellosis include diarrhea, fever, stomach cramps, and nausea. While it's not usually life-threatening, it can be hazardous for vulnerable populations such as children, older adults, or those with weakened immune systems.

Make sure all team members understand the importance of handwashing and have access to clean, running water. Keep food storage areas clean and separated from raw meat and other potentially hazardous foods. And, of course, always ensure your ingredients are fresh and safe for consumption. 

10. Yersinia

Yersinia, also known as Yersiniosis, is a bacterial infection that can affect animals and humans. It is caused by the Yersinia bacteria, which can be found in various foods like raw or undercooked meat, poultry, and fish.

The symptoms of Yersinia infection generally start within three to seven days after being exposed to the bacteria and include fever, abdominal pain, diarrhea, nausea, and vomiting. In some rare cases, the infection can lead to more serious complications like reactive arthritis.

Again, practicing good hygiene and avoiding cross-contamination is critical to preventing the spread of Yersinia.

11. Cyclospora 

Last but not least, we have Cyclospora. That is a parasite typically found in contaminated water or food that has been exposed to contaminated water, such as produce that has been rinsed in it. The parasite is most commonly found in tropical and subtropical regions. Still, as our food system becomes increasingly connected on a global level, cases have been popping up all over the world in recent years.

As for symptoms of Cyclospora, they often include stomach cramps, diarrhea, nausea, and fatigue. In some cases, the symptoms can last for weeks or even months. It's important to note that not everyone infected will experience symptoms, but they can still spread the parasite to others.

So, how can you prevent Cyclospora from infecting your customers? First and foremost, properly washing and handling produce is critical. Make sure your produce is thoroughly rinsed and dried before serving. Making sure that your water sources are clean and properly treated can prevent contamination. 

How to Protect Yourself and Your Customers From Foodborne Illnesses

Now that you know some of the most common foodborne illnesses that can affect your customers, let’s take a more detailed look at how to prevent them. 

Keep Things Clean

First things first, "Keep things clean." That might sound like common sense, but it's worth reiterating. Proper hygiene practices are vital to preventing the spread of harmful bacteria and viruses.

According to the National Library of Medicine, about 64% of foodborne illness outbreaks are associated with poor health and hygiene practices.9

Ensure all surfaces, utensils, and equipment are regularly cleaned and sanitized. Frequently washing your hands is crucial, especially after handling raw meat or using the toilet.

Separate Ingredients

Keep meats, poultry, seafood, and eggs separate from fruits and vegetables to prevent cross-contamination.

Store raw meats at the bottom of the fridge so any drips won't contaminate other foods, and always use separate cutting boards and utensils for different ingredients.

Cook Food to the Proper Temperatures

Undercooked meat, poultry, and seafood can contain harmful bacteria that cause food poisoning.

Use a thermometer to check that food is cooked to the appropriate internal temperature, and keep hot food hot (above 60°C) and cold food cold (below 5°C).

Ensure Good Staff Hygiene

About 40% of US foodborne illness outbreaks are traced back to workers who came in sick.10

Long story short here? It’s not worth it. Encourage your staff to stay home if they're sick and provide them with sick days. Proper uniform and hair coverings are also important, as are proper hand-washing protocols. 

Chill Food That Needs It 

Chilling food is just as important as cooking it. Keep perishable items like meat, dairy, and produce stored at the correct temperature, and ensure they don't reach the 'danger zone' (between 4°C and 60°C).

Proper temperature regulation applies during transport, so ensure you or your suppliers transport food in a chilled environment when needed.

What to Do if There’s a Foodborne Illness Outbreak

So you’ve done everything you can to prevent a foodborne illness outbreak–but then, without warning, disaster strikes. A customer is sick, and your restaurant is to blame.

First things first, it's important to understand that time is of the essence in these situations. The longer you wait to take action, the more people could become sick.

Next, try not to panic. 

If you suspect a foodborne illness outbreak, you should alert your local health department first. They will investigate and provide guidance on what steps to take next. It's also important to notify your staff and any customers who may have eaten at your establishment during the affected period. Communication is critical in these situations.

It's important to gather as much information as possible about the outbreak. That includes the symptoms exhibited by those who became ill, the menu items they consumed, and the timeframe in which they ate. The health department uses this information to identify the outbreak's source and prevent future occurrences.

If you’re able to pinpoint the cause, put it on lockdown. Remove that food from your kitchen or facility and ensure it doesn't come into contact with other food items. 

In the meantime, it's important to sanitize your entire establishment thoroughly. That includes all surfaces, utensils, and cookware. Any contaminated food should be disposed of properly. It can be challenging to determine which items are contaminated, so it's best to err on the side of caution and throw away anything that may have been affected.

Once everything has been sanitized, it's important to implement new policies and procedures to prevent future outbreaks. That may include stricter food handling guidelines, new inspection procedures, sick leave policies, or staff training on food safety.2

The Takeaway

You already know that serving delicious food is a part of the job–but keeping your customers healthy and safe is just as important. It can be tough to stay on top of all the guidelines and regulations around food safety, but educating yourself on the most common foodborne illnesses is a step in the right direction.

At Trust20, food safety is at the core of everything we do. We offer a suite of products for foodservice professionals that help ensure compliance with regulations and best practices, including online training courses, a certification program, and digital food safety plans.

With Trust20, you can rest easy knowing that you're taking all the necessary steps to keep your customers well-fed, satisfied, and most importantly–safe.

New call-to-action


  1. CDC: Estimates of Foodborne Illness in the United States
  2. CDC: Foodborne Illness Outbreaks at Retail Food Establishments — National Environmental Assessment Reporting System, 25 State and Local Health Departments, 2017–2019 
  3. CDC: Questions and Answers | Estimates of Foodborne Illness
  4. CDC: Norovirus Burden and Trends
  5. FDA: Most Common Foodborne Illnesses
  6. CDC: Foodborne Germs and Illnesses
  7. Healthline: 17 of the Worst Foodborne Illness Outbreaks in U.S. History
  8. CDC: Guillain-Barré Syndrome | Campylobacter
  9. L. Hannah Gould et al: Contributing Factors in Restaurant-Associated Foodborne Disease Outbreaks
  10. Mary Van Beusekom, MS: 40% of US foodborne restaurant outbreaks traced to sick workers