Listeria Prevention for Restaurants

What are Listeria?

In May of 2023, an outbreak of listeria occurred at the fast food chain “Frugal’s” in Tacoma, WA. The outbreak caused six hospitalizations and three deaths. The culprit? An incorrectly cleaned ice cream machine.

Listeria are a family of bacteria that can cause foodborne illness. Listeria monocytogenes live everywhere—air, water, soil, and near or on animals. The pervasiveness of this bacterium challenges food service professionals and restaurant owners in the prevention of listeria. Another challenge is the longevity of listeria, which can cause an infection up to 70 days after exposure.

Listeria infection causes a disease called listeriosis. Symptoms may include diarrhea, stomach cramps, vomiting, and other flu-like symptoms, but the symptoms are mild for many individuals. People in immunocompromised groups are particularly at risk, with a mortality rate of up to 30% in these groups—even with antibiotic treatment.

Research from Johns Hopkins University estimates that restaurants can incur substantial losses from a foodborne illness outbreak, anywhere from a few thousand dollars to several million when afflicted customers decide to sue.

With proper planning and sanitation, restaurant teams can mitigate the risk of listeria outbreaks. This post will explore how listeria spreads, at-risk populations, and effective prevention measures.

How are listeria spread?


Unlike similar pathogens, listeria grow at refrigerated temperatures (40 degrees Fahrenheit and below). This fact means that ready-to-eat (RTE) foods, such as smoked seafood, deli salads, and other RTE products, are particularly susceptible to incubating listeria. Different types of food are also at high risk of listeria contamination:

  • Raw dairyAccording to the FDA, foods made with unpasteurized raw milk, including cheese, can be up to 160 times more likely to incubate listeria.
  • Raw seafood – Oysters and other raw fish preparations.
  • Deli foods – Deli meats and cheeses.
  • Vegetables and fruit – Raw fruit and vegetables, including leafy greens.


Because listeria thrives in most environments, cleaning and sanitizing all kitchen surfaces is critical. Some problem areas in commercial kitchens include grease traps, air vents/filters, drains, floors, walls, and ceilings. Eliminating vermin infestations is also crucial, as insects or rodents can spread listeria.


Hard-to-clean equipment has long been a culprit in listeria outbreaks. Nooks and crannies provide ideal breeding grounds for listeria that can evade rags and sponges. When cleaning, take special care in sanitizing:

  • Deli slicers
  • Refrigerated display cases (especially the cooling fans)
  • Wheels on transport carts

Additionally, damaged equipment might create cracks that listeria can hide in.


Unfortunately, employees are common spreaders of listeria. A key to listeria prevention is properly training staff in sanitation and food safety. Individuals can carry listeria monocytogenes in their intestines (often without symptoms) for over two months. Improper handwashing, unwashed uniforms or aprons, and improper food handling by employees can all exacerbate or cause listeria to spread.

Also read: Outdoor Dining Safety Checklist: Are You Ready?

At-risk populations

According to the CDC, Listeria is the third leading cause of foodborne illness death in the U.S. While most healthy individuals face mild symptoms from listeria, certain groups are at a much higher risk:

  • Pregnant women are ten times more likely to contract a listeria infection, with Latinx women facing an even higher risk. It’s thought that pregnant Latinx women are more likely to contract listeriosis because of the raw soft cheeses (queso fresco, for example) that are common in Hispanic food. Not only are the women themselves at risk, but listeria can also infect the unborn fetus.
  • The elderly and immunocompromised individuals, such as those with HIV/AIDS, cancer, diabetes, kidney disorders, or transplant recipients, also face an elevated risk of contracting listeria.

These populations should limit or reduce exposure to high-risk foods. Restaurants can also choose not to serve raw or unpasteurized foods to minimize risk. However, this is impossible for certain restaurants (sushi bars, oyster bars, etc.). That is why many restaurants post warnings about consuming undercooked or raw food.

What can restaurants do to prevent listeria?

Proper sanitation

By following the basics of sanitation, restaurants can stop the spread of listeria and prevent outbreaks. The basics are summed up neatly by the CDC in four simple steps:

  1. Clean and sanitize – Wash all prep surfaces, utensils, plates, cups, pots, pans, and instruments with hot water and soap. Regularly clean the previously mentioned problem areas, including drains, grease traps, ceilings, and air filters. Sanitize everything with diluted bleach or a food service sanitizer. Most importantly, train your staff on proper sanitation techniques and implement a rigid cleaning schedule. Consult local food safety guidelines to ensure your kitchen is up to code.
  2. Separate – Properly separate raw meat, fish, and other high-risk foods to prevent contamination with other ingredients. For example, keep meat cutting boards, knives, and storage containers separate from other ingredients.
  3. Cook – It is crucial to confirm that raw food reaches food-safe temperature. Use a food thermometer; don’t rely on ingredient appearance. Safe internal temperatures vary based on the ingredient, so it’s best to consult a food temperature chart. To lower the risk of RTE foods, ensure proper temperature-controlled storage and never use a product past its expiration date.
  4. Chill – Make sure you properly store cooked and uncooked ingredients. Refrigerators must maintain temperatures below 40 degrees Fahrenheit and freezers below 0 degrees Fahrenheit.

Learn more: 5 Steps Your Restaurant Can Take to Reduce Foodborne Illness Liability

Be proactive

It’s not enough to wait for an outbreak to occur. Restaurant owners should develop an outbreak response plan so that everyone on their team knows what to do in case of reports of listeriosis. Additionally, restaurants should consider regular inspections or even bacteria testing from third parties as a proactive tool for listeria prevention.

Prepare for the worst-case scenario

Unfortunately, listeria outbreaks still occur despite the best efforts of talented chefs and their staff. All it takes is a simple mistake to expose your restaurant to negative press, costly litigation, and reputational damage. Part of prevention is ensuring your insurance coverage is ready to handle an outbreak.

McGowan Program Administrators are well-versed in the perils of the restaurant industry. We provide the specific insurance products your restaurant needs to mitigate risk and protect employees, owners, and patrons. Our Restaurants, Bars, and Taverns Insurance policies are customizable and comprehensive to ensure your establishment to safeguard your assets.

To learn more about preventing the spread of listeria and other pathogens in kitchens, download our free e-book: Preventing Foodborne Diseases In Restaurants.

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