History of Listeria: Who Discovered It and When?

Published on: July 15, 2023

A Floridian’s Guide to Staying Safe

Introduction

Meet Listeria monocytogenes, or Listeria for short. This resilient bacterium can cause a potentially severe infection called listeriosis. The infection is especially dangerous for pregnant women and newborns, adults aged 65 or older, and people with weakened immune systems.

Although listeriosis is relatively rare, it can cause serious or life-threatening complications. According to the Centers for Disease Control and Prevention, approximately 1,250 people in the United States are infected with Listeria each year, and about 172 people die from the infection.

People throughout the country, including Florida residents, should understand Listeria’s history, how it spreads, the symptoms it can cause, available treatments, and how to help prevent infection.

In this article, we will explore the history of Listeria, answer who discovered Listeria monocytogenes and when, review its symptoms and treatment, share prevention tips, and examine notable outbreaks and recalls affecting Florida. Our goal is to give you practical information that can help protect you and your loved ones.

If you ate food connected to a Listeria recall or are concerned about possible symptoms, contact your healthcare provider. This is particularly important if you are pregnant, aged 65 or older, or living with a weakened immune system.

Who Discovered Listeria Monocytogenes?

Listeria monocytogenes was first isolated in 1924 by British bacteriologist E.G.D. Murray and his colleagues R.A. Webb and M.B.R. Swann while investigating a sudden and fatal infection among laboratory animals. The researchers published their description of the bacterium in 1926 under the name Bacterium monocytogenes.

This distinction explains why some sources say Listeria was discovered in 1924, while others cite 1926. The bacterium was first isolated in 1924, but the researchers’ scientific description was published two years later.

Murray and his colleagues initially isolated the bacterium from laboratory guinea pigs and rabbits that had developed a sudden and fatal infection. The discovery marked the first recorded identification of the pathogen and became an important moment in the history of infectious disease research.

When Was Listeria Discovered?

The history of Listeria involves several important dates:

According to the CDC’s history of Listeria, the bacterium was first isolated by Murray in 1924 as Bacterium monocytogenes. The name Listeria was proposed in 1940.

Why Was Listeria Named After Joseph Lister?

Listeria was named in honor of British surgeon Sir Joseph Lister, an early advocate for antiseptic surgery. However, Joseph Lister did not discover Listeria monocytogenes.

Pirie initially proposed the name Listerella in 1927. After discovering that the name had already been assigned to another organism, he proposed Listeria as an alternative in 1940. This historical distinction is important because Joseph Lister inspired the bacterium’s name, while Murray and his colleagues were responsible for its original isolation and scientific description.

Early History of Listeria

The discovery of Listeria monocytogenes was pivotal because it eventually led to a deeper understanding of a bacterium associated with serious infections and numerous foodborne outbreaks worldwide.

In the years following its discovery, researchers found that Listeria monocytogenes was present not only in laboratory animals but also in natural environments. It was detected in soil, water, and vegetation, demonstrating its widespread environmental presence. This distribution makes the bacterium particularly challenging to control and helps explain how food may become contaminated.

As research progressed, it became evident that Listeria monocytogenes could survive and even grow under conditions that are inhospitable to many other bacteria. It can tolerate low temperatures, high salt concentrations, and acidic environments. This resilience contributes to its ability to contaminate foods ranging from raw fruits and vegetables to processed and ready-to-eat products.

Over the decades since its discovery, outbreaks of listeriosis have occurred worldwide, often after people consumed contaminated food. One of the most notable outbreaks occurred in California during the 1980s and was linked to contaminated cheese. This outbreak increased awareness of Listeria contamination and contributed to changes in food-safety regulations and practices.

Recent Advances in Listeria Research

Advances in molecular biology and genomics have provided researchers with new insights into the virulence mechanisms of Listeria monocytogenes and its ability to cause disease.

Researchers have identified genes and biological pathways that contribute to the bacterium’s ability to invade host cells, evade parts of the immune system, and cause infection. Whole genome sequencing also allows public health investigators to compare Listeria samples collected from patients, foods, and food-processing environments. This can help identify connections between infections and potential outbreak sources.

Despite these advances, Listeria monocytogenes continues to present a significant public health concern. Controlling its spread and preventing outbreaks remain priorities for food-safety authorities worldwide.

Why Listeria Is Difficult to Control

Listeria can be present in soil, water, vegetation, and certain animals, including poultry and cattle. It can also contaminate numerous food products, such as:

• Raw or unpasteurized milk
• Certain soft cheeses
• Deli meats
• Hot dogs
• Refrigerated pâtés and meat spreads
• Smoked seafood
• Prepared salads
• Raw fruits and vegetables
• Processed and ready-to-eat foods

Unlike many other foodborne bacteria, Listeria monocytogenes can survive and multiply at temperatures commonly found in refrigerators. Refrigeration can slow the growth of many bacteria, but it does not necessarily eliminate Listeria.

Although Florida is not known for having a major dairy industry, contaminated products can still enter the state through regional and national food distribution networks. Florida residents should therefore follow food recalls and use safe food-handling practices regardless of where a product was manufactured.

Listeriosis Symptoms

The symptoms of listeriosis can vary depending on the individual and whether the infection remains in the intestinal tract or spreads beyond it.

Early or intestinal symptoms may include:

• Fever
• Muscle aches
• Nausea
• Diarrhea
• Fatigue

If the infection becomes invasive and affects the nervous system, symptoms may include:

• Headache
• Stiff neck
• Confusion
• Loss of balance
• Convulsions

Pregnant women may experience only mild symptoms, such as fever, fatigue, and muscle aches. However, the infection can have severe consequences for the pregnancy, including miscarriage, stillbirth, premature delivery, or infection in the newborn.

Some people may experience mild symptoms, while others can develop severe and potentially life-threatening complications. Prompt medical attention is especially important for people in higher-risk groups who develop symptoms after eating food recalled or linked to a Listeria outbreak.

If you develop fever, muscle aches, digestive symptoms, confusion, a stiff neck, or other concerning symptoms after possible Listeria exposure, contact a healthcare provider promptly. Seek emergency care for severe or life-threatening symptoms.

Treatment and Care for Listeria

Treatment for listeriosis depends on the type and severity of the illness, the patient’s risk factors, and whether the infection has become invasive.

Invasive listeriosis is generally treated with antibiotics. Ampicillin may be used, sometimes in combination with gentamicin, depending on the patient’s condition and the treating clinician’s judgment. Trimethoprim-sulfamethoxazole may be considered in certain situations, including for some patients who cannot take penicillin. Medication choices should always be made by a qualified healthcare professional based on the individual patient.

Treatment is most effective when a serious infection is recognized and addressed promptly. Hospitalization may be required in severe cases, particularly when the infection has spread to the bloodstream or nervous system.

The CDC states that treatment depends on the kind and severity of the illness. People experiencing diarrhea should drink adequate fluids to help prevent dehydration unless a healthcare provider has advised otherwise.

Contact a healthcare provider if you have a fever or other symptoms of listeriosis, such as fatigue and muscle aches, especially after eating food that has been recalled or linked to an outbreak. This precaution is particularly important for pregnant women, adults aged 65 or older, and people with weakened immune systems.

If you recently ate food that may have been contaminated but do not feel sick, testing or treatment may not be necessary. However, you should speak with a healthcare provider if you have questions about your exposure, personal risk factors, or what symptoms to monitor.

Tampa Bay patients with concerns about infectious disease care can call Infectious Disease Associates of Tampa Bay at 813-251-8444 to ask about the appropriate next step.

Preventing Listeriosis

Preventing listeriosis involves practicing good hygiene, handling food safely, and being cautious with foods more commonly associated with contamination.

Here are several practical prevention tips for Floridians and others:

1. Wash your hands and surfaces: Wash your hands thoroughly with soap and water before and after handling food. Clean utensils and food-preparation surfaces in your home or commercial kitchen with hot, soapy water.
2. Cook food thoroughly: Cook meat, poultry, and eggs thoroughly. Use a food thermometer to confirm that food has reached a safe internal temperature.
3. Store food properly: Refrigerate or freeze perishable foods, prepared foods, and leftovers within two hours of purchasing, preparing, or cooking them.
4. Be cautious with high-risk foods: Avoid raw or unpasteurized milk and products made from it. People at higher risk should also exercise additional caution with certain soft cheeses, deli meats, refrigerated smoked seafood, and other ready-to-eat products.
5. Reheat deli meats when appropriate: People at higher risk should follow current public health guidance regarding deli meats and hot dogs, including reheating recommendations.
6. Practice safe food handling: Wash fruits and vegetables thoroughly under running water before eating, cutting, or cooking them.
7. Prevent cross-contamination: Keep raw food separate from cooked and ready-to-eat food. Clean refrigerator shelves, containers, utensils, and countertops that may have contacted a recalled product.
8. Follow food recalls: Check current FDA and CDC recall notices rather than relying on older articles to determine whether a product is currently affected.

These steps can reduce the risk of listeriosis, but they cannot guarantee that every exposure will be prevented. People in high-risk groups should follow recommendations from their healthcare providers and public health authorities.

Notable Listeria Outbreaks and Recalls Affecting Floridians

The following incidents are historical examples. They are not necessarily active recalls. Consumers should consult current FDA and CDC notices for up-to-date food-safety alerts.

Smoked Salmon Recall at Publix Stores

In one incident, salmon sold at Florida Publix stores was recalled because of potential Listeria contamination.

According to WFLA’s report, the U.S. Food and Drug Administration announced the recall of smoked salmon products sold in Publix stores across Florida. Routine testing revealed the presence of Listeria monocytogenes in the product. Consumers were advised to return the affected product to the store for a refund or dispose of it properly to avoid potential health risks.

2023 Salad Kit Recall at Publix Stores

In April 2023, salad kits sold at Publix stores in Florida were recalled over Listeria concerns.

According to WESH, the recall involved several salad kits distributed to stores in Florida and other states. The affected Fresh Express products were identified after Listeria was detected during random sampling by the Georgia Department of Agriculture. Consumers were advised to follow the recall instructions and request a refund where the products were purchased.

2022 Vidalia Onion Recall

The Ledger reported a recall of Vidalia onions sold at Publix stores because of possible Listeria contamination.

The affected onions were distributed to retailers in multiple states, including Florida. The recall was initiated after routine testing revealed the presence of Listeria monocytogenes on equipment used to pack the onions. Consumers were advised to check their homes for the recalled onions and return them to the store for a refund or dispose of them properly.

2022 Listeria Outbreak Linked to Big Olaf Creamery in Sarasota

An outbreak of Listeria monocytogenes infections linked to ice cream supplied by Big Olaf Creamery in Sarasota, Florida resulted in 28 reported illnesses across 11 states.

The FDA and CDC assisted the Florida Department of Health and Florida Department of Agriculture and Consumer Services with the investigation. Investigators found that Big Olaf ice cream products were the likely source of the outbreak.

Big Olaf Creamery ceased production and distribution on July 1, 2022, and initiated a voluntary recall covering all flavors, lots, codes, and expiration dates through June 30, 2022. The products had been sold at Big Olaf retailers in Florida, as well as restaurants, senior living facilities, and one location in Fredericksburg, Ohio.

The FDA reported 27 hospitalizations, one death, and one fetal loss associated with the outbreak. One case involved the death of an Illinois woman, while another involved a Massachusetts resident who experienced a miscarriage. Legal claims alleged that the Illinois woman died after consuming Big Olaf ice cream in Sarasota and that the Massachusetts resident ate contaminated ice cream at a wedding in Clearwater.

The outbreak was declared over in November 2022. It demonstrates the potentially severe consequences of foodborne illness and the importance of routine testing, timely recalls, environmental monitoring, and proper food-safety practices.

What Should You Do After Possible Listeria Exposure?

What you should do depends on whether you have symptoms and whether you are at increased risk of severe illness.

You Ate a Recalled Food but Have No Symptoms

Testing or treatment may not be necessary for most people who remain well. Monitor your health and speak with a healthcare provider if you have questions about your individual risk.

You Develop Symptoms After Eating Recalled Food

Contact a healthcare provider and explain what you ate, when you ate it, and when your symptoms began. Keep any packaging, product codes, receipts, or recall information that may help identify the product.

You Are Pregnant, Aged 65 or Older, or Immunocompromised

Contact your healthcare provider promptly if you develop fever, fatigue, muscle aches, digestive symptoms, or other signs of illness after possible exposure. These groups face a higher risk of invasive listeriosis and serious complications.

You Develop Severe Symptoms

Seek urgent medical care for severe symptoms such as confusion, convulsions, loss of balance, a stiff neck, breathing difficulty, or other potentially life-threatening problems.

Frequently Asked Questions About Listeria

Who discovered Listeria monocytogenes?

British bacteriologist E.G.D. Murray and his colleagues R.A. Webb and M.B.R. Swann first isolated Listeria monocytogenes in 1924 while investigating illness among laboratory animals.

When was Listeria discovered?

The bacterium was first isolated in 1924, and the researchers published their scientific description in 1926. This is why both dates may appear in accounts of the history of Listeria.

Did Joseph Lister discover Listeria?

No. Joseph Lister did not discover the bacterium. Listeria was named in his honor because of his influential work promoting antiseptic surgical practices.

When did the name Listeria become official?

J.H. Harvey Pirie proposed the name Listeria in 1940 after learning that his previously proposed name, Listerella, had already been used for another organism.

When was Listeria recognized as a foodborne pathogen?

Listeria became widely recognized as an important foodborne pathogen during the 1980s following investigations of major outbreaks linked to contaminated foods.

Can Listeria grow in a refrigerator?

Yes. Unlike many other bacteria, Listeria monocytogenes can survive and multiply at refrigeration temperatures. Proper refrigeration remains important, but it does not eliminate the bacterium.

Who is most at risk of severe listeriosis?

Pregnant women and newborns, adults aged 65 or older, and people with weakened immune systems face the greatest risk of serious complications.

What should I do if I ate food recalled for Listeria?

If you do not have symptoms, testing or treatment may not be necessary. Contact a healthcare provider if symptoms develop, if you belong to a high-risk group, or if you have questions about your exposure.

Protecting Yourself and Your Family From Listeria

Listeria is a dangerous bacterium that can cause a potentially fatal infection called listeriosis. Although the infection is relatively rare, Floridians and others should understand the risks and take appropriate precautions.

Practicing good hygiene, cooking food thoroughly, storing food properly, preventing cross-contamination, monitoring food recalls, and being cautious with high-risk foods can help reduce the risk of infection.

Historical outbreaks, such as the Florida outbreak linked to Big Olaf Creamery, also highlight the importance of routine testing and timely recalls. Consumers should follow recommendations from public health authorities, check their homes for recalled products, and return or safely dispose of affected food.

If you or someone you know develops symptoms of listeriosis, particularly after consuming recalled food, seek medical guidance promptly. Staying informed and following evidence-based food-safety practices can help protect you and your loved ones from this serious infection.

About Infectious Disease Associates of Tampa Bay

Infectious Disease Associates of Tampa Bay provides high-quality healthcare services for patients throughout the Tampa Bay metro area. With more than 30 years of experience, IDATB has treated Floridians with infectious diseases while providing an in-house laboratory for necessary testing.

If you have questions about Listeria or concerns about another infectious disease, call IDATB at 813-251-8444 to ask about the appropriate next step. Seek emergency medical care immediately for severe or life-threatening symptoms.