Avoiding Listeriosis

Listeria monocytogenes has been in the news and on the recall lists recently, both here in the US and in Europe. This week there have been lettuce, premade salads, green and black olives, mozzarella and muenster cheese, and smoked salmon recalls for Listeria monocytogenes. I thought that we might take a closer look at how you can help protect yourself from this foodborne pathogen. Listeria monocytogenes (Lm) is a bacterial pathogen that is frequently found in the environment. It is ubiquitous. It can be found in the water, soil, and in and on plants, so it can show up frequently in lettuce, cantaloupes, melons, and other fruits and vegetables that are not thermally processed. But that isn’t the only place it can be found, it can be found on people, equipment, ingredients, and anywhere that has had contact with contaminated soil, water, or plants. The world is not a sterile place, and neither is the food we consume (1).

Who is susceptible to Listeria monocytogenes?

According to the CDC, approximately 260 people per year die from listeriosis. Estimations put the cases of the disease at around 1600 per year. While this is not an extremely high number of cases compared to other foodborne diseases such as Salmonella, it is one of the deadliest (2).  Everyone is susceptible to the disease, but for some select groups, the illness can be much more severe, which can result in death. The more susceptible groups are older adults, people with weakened immune systems, and pregnant women.

How do I know if I am a person who is considered at risk?

If you are over the age of 65, you are 4 times as likely to contract listeriosis. As we age, our immune systems do not work quite as well, and they don’t recognize bacteria and viruses as well as they did when we were younger (2). This is why Covid and the flu are also likely to be contracted at older ages unless you have been immunized. Immunization helps prepare our immune systems to recognize foreign invaders sooner. However, there is no vaccine for listeriosis, so we have to avoid the bacteria.  If you have the following conditions, you are also more prone to contracting listeriosis: cancer, liver or kidney disease, alcoholism, diabetes, HIV or AIDs, and organ transplant recipients are more likely to contract the disease (2). Certain medications such as antacids, medications for gastritis and ulcers, steroids and chemotherapy drugs can also inhibit the immune system’s ability to fight invading bacteria (2). According to CDC statistics, cancer patients are 10 times more likely to contract the disease, and dialysis patients are 50 times more likely to get infected than the general population (2). Pregnant women are also at risk. They are 10 times more likely than other people to get an infection with Listeria and the CDC states that Hispanic women are 24 times more likely than the general population to contract this illness (2), for more information from the CDC, check out this link https://www.cdc.gov/listeria/risk.html.

If I buy premade or packaged foods, am I safe?

There are no guarantees when it comes to pre-made or prepackaged foods. Manufacturers and other food-handling establishments normally have a food safety plan in place that considers the biological, chemical, and physical hazards that could contaminate foods in their facilities. Remember, some foods are inherently more likely to contain Listeria spp. than others. Choosing safer foods is the easiest thing to do if you happen to be in one of the higher-risk groups. Unpasteurized cheeses, milk and other dairy products, deli meats, cold cuts, hot dogs, pre-made deli sandwiches and salads, refrigerated pate or meat spreads, refrigerated smoked meats or fish, sprouts, and pre-cut melons (2). There are safer alternatives that can be found here: https://www.cdc.gov/listeria/prevention.html

Anytime cooked food is handled, there is always a chance of listeria being introduced back into the product. This is why it is so important to make sure that handwashing and using sanitizers are stressed when handling foods.

What should I do if I prepare food at home to minimize the risks?

Minimizing your risk at home is easy if you use basic food safety measures (2).

• Don’t forget to wash your hands! Use soap and running water while washing for a minimum of 20 seconds.
• Use a food thermometer to ensure that your foods have reached the recommended temperatures https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/safe-temperature-chart (3).
• Wash raw produce before cutting, or peeling.
• Do not wash eggs, uncooked meats, or poultry.
• Keep raw meat separate from ready-to-eat or raw foods.
• Marinate meats in the refrigerator.
• Do not thaw items on the counter. Use the refrigerator instead.
• Within 2 hours of cooking, make sure to refrigerate your leftovers.
• Use shallow containers for leftovers. They cool faster.
• Make sure that your refrigerator is cooling to 40 °F or below, and that your freezer is at least 0 °F.
•  Use separate cutting boards and utensils for raw and cooked or ready-to-eat foods.
• For more information check out https://www.cdc.gov/listeria/risk-groups/weakened-immunity.html

How can I reduce the risk of contracting listeriosis?

To reduce the risks, follow good hygiene and food safety practices at home and when you are out and about. Be careful which foods you choose when purchasing Deli food. Many pieces of deli equipment are hard to clean properly every few hours. It only takes a few hours at room temperature for bacteria to multiply.

 Make sure that any refrigerated foods stay cold. If salads or sandwiches are not refrigerated, give them a pass. Check out any food preparation areas that you can see. Are they practicing good food safety habits? Do not use drive-thru windows at a new restaurant without scoping out the inside of the establishment. Stay informed about food recalls and check your pantry and refrigerator frequently to rotate out foods that have expired or have been pushed to the back of the for a while.

Basic food safety is always a good idea, especially if you have loved ones who are more susceptible to becoming a foodborne illness statistic. Help keep your loved ones safe by washing your hands, separating raw and cooked foods and separate utensils, refrigerating your leftovers quickly, and using a food thermometer. These simple rules can make a huge difference in the safety of the food that you prepare for your family. As always, wash your hands, stay safe, and keep an eye out for food safety hazards!

Sources

1. Government Relations Team, Fspca Preventive Controls for Human Food (CreateSpace Independent Publishing Platform, 2016; https://play.google.com/store/books/details?id=-3aODAEACAAJ).
2.  CDC, People at Risk. Centers for Disease Control and Prevention (2022), (available at https://www.cdc.gov/listeria/risk.html).
3. Safe Minimum Internal Temperature Chart, (available at https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/safe-temperature-chart).