--- title: "Salmonella vs. Listeria: What's the difference?" date: 2023-09-30T12:36:00-07:00 author: Julie Dueck canonical_url: "https://marlerclark.com/news_events/salmonella-vs-listeria-whats-the-difference" section: News --- [All News](/news_events) / [Firm News](https://marlerclark.com/news_events/firm-news) / # Salmonella vs. Listeria: What's the difference? *Salmonella* is a bacterium that causes one of the most common enteric (intestinal) infections in the United States: salmonellosis. The term *Salmonella* refers to a group or family of bacteria that cause various illnesses in humans. *Salmonella* serotype typhimurium and *Salmonella* serotype enteritidis are the most common in the U.S. *Salmonella* are found in the intestinal tract of wild and domesticated animals and humans. Some serotypes of *Salmonella*, such as *S.* Typhi and *S.* Paratyphi are only found in humans. For ease of discussion, it is generally useful to group *Salmonella*e into two broad categories: Typhoidal, which includes *S*. Typhi and *S*. Paratyphi, and non-typhoidal, which includes all other serotypes. *Salmonella* can be grouped into more than 2,400 serotypes. The two most common serotypes in the U.S. are *S.*Typhimurium and *S.*Enteritidis. *S.*Typhi, the serotype that causes typhoid fever, is uncommon in the U.S. Globally, typhoid fever continues to be a significant problem, with an estimated 12-33 million cases occurring annually. Moreover, outbreaks in developing countries have a high death rate, especially when caused by strains of the bacterium that are resistant to antibiotic treatment. In 2009, over 40,000 cases of Salmonella (13.6 cases per 100,000 persons) were reported to the CDC by public health laboratories across the nation, representing a decrease of approximately 15 percent from the previous year, but a 4.2 percent increase since 1996. Overall, the incidence of *Salmonella* in the U.S. has not significantly changed since 1996. Only a small proportion of all *Salmonella* infections are diagnosed and reported to health departments. It is estimated that for every reported case, there are approximately 38.6 undiagnosed infections. The CDC estimates that 1.4 million cases, 15,000 hospitalizations, and 400 deaths are caused by *Salmonella* infections in the U.S. every year. *Listeria* is a gram-positive rod-shaped bacterium that can grow under either anaerobic (without oxygen) or aerobic (with oxygen) conditions. Of the six species of *Listeria*, only *L. monocytogenes* causes disease in humans. These bacteria multiply best at 86-98.6 degrees F (30-37 degrees C), but also multiply better than all other bacteria at refrigerator temperatures, something that allows temperature to be used as a means of differentiating *Listeria* from other contaminating bacteria. Called an “opportunistic pathogen,” *Listeria* is noted to cause an estimated 2,600 cases per year of severe invasive illness. Perhaps not surprisingly then, “foodborne illness caused by *Listeria monocytogenes* has raised significant public health concern in the U.S., Europe, and other areas of the world.” Given its widespread presence in the environment and food supply, the ingestion of *Listeria* has been described as an “exceedingly common occurrence.” *Listeria* bacteria are found widely in the environment in soil, including in decaying vegetation and water, and may be part of the fecal flora of many mammals, including healthy human adults. According to the FDA, “studies suggest that up to 10 percent of humans may be intestinal carriers of *Listeria*.” Another authority notes that the “organism has been isolated from the stool of approximately five percent of healthy adults.” Overall, seasonal trends show a notable peak in total *Listeria* cases and related deaths from July through October. Ingested by mouth, *Listeria* is among the most virulent foodborne pathogen, with up to 20 percent of clinical infections resulting in death. These bacteria primarily cause severe illness and death in persons with immature or compromised immune systems. Consequently, most healthy adults can be exposed to *Listeria* with little to any risk of infection and illness. Among adults 50 years of age and older, infection rates were estimated to have declined from 16.2 per one million in 1989 to 10.2 per one million in 1993. Perinatal disease decreased from 17.4 cases per 100,000 births in 1989 to 8.6 cases per 100,000 births in 1993. Neonatal infections are often severe, with a mortality rate of 25 to 50 percent. ### Lawsuit updates about foodborne illnesses [Reactive Arthritis Lawsuit Updates](/news_events/case-news?illness=reactive-arthritis&year=all) [E. coli Lawsuit Updates](/news_events/case-news?illness=e-coli&year=all) [Guillain-Barre Syndrome Lawsuit Updates](/news_events/case-news?illness=guillain-barre-syndrome&year=all) [Salmonella Lawsuit Updates](/news_events/case-news?illness=salmonella&year=all) [Hemolytic Uremic Syndrome Lawsuit Updates](/news_events/case-news?illness=hemolytic-uremic-syndrome&year=all) [Listeria Lawsuit Updates](/news_events/case-news?illness=listeria&year=all) [Irritable Bowel Syndrome Lawsuit Updates](/news_events/case-news?illness=irritable-bowel-syndrome&year=all) [Hepatitis A Lawsuit Updates](/news_events/case-news?illness=hepatitis-a&year=all) [Norovirus Lawsuit Updates](/news_events/case-news?illness=norovirus&year=all) [Botulism Lawsuit Updates](/news_events/case-news?illness=botulism&year=all) [Campylobacter Lawsuit Updates](/news_events/case-news?illness=campylobacter&year=all) [Shigella Lawsuit Updates](/news_events/case-news?illness=shigella&year=all) [Cyclospora Lawsuit Updates](/news_events/case-news?illness=cyclospora&year=all) ### Lawsuits updates by year [Foodborne Illness Lawsuits in 1998](https://marlerclark.com/news_events/case-news?illness=all&year=1998) [Foodborne Illness Lawsuits in 1999](https://marlerclark.com/news_events/case-news?illness=all&year=1999) [Foodborne Illness Lawsuits in 2000](https://marlerclark.com/news_events/case-news?illness=all&year=2000) [Foodborne Illness Lawsuits in 2001](https://marlerclark.com/news_events/case-news?illness=all&year=2001) [Foodborne Illness Lawsuits in 2002](https://marlerclark.com/news_events/case-news?illness=all&year=2002) [Foodborne Illness Lawsuits in 2003](https://marlerclark.com/news_events/case-news?illness=all&year=2003) [Foodborne Illness Lawsuits in 2004](https://marlerclark.com/news_events/case-news?illness=all&year=2004) [Foodborne Illness Lawsuits in 2005](https://marlerclark.com/news_events/case-news?illness=all&year=2005) [Foodborne Illness Lawsuits in 2006](https://marlerclark.com/news_events/case-news?illness=all&year=2006) [Foodborne Illness Lawsuits in 2007](https://marlerclark.com/news_events/case-news?illness=all&year=2007) [Foodborne Illness Lawsuits in 2008](https://marlerclark.com/news_events/case-news?illness=all&year=2008) [Foodborne Illness Lawsuits in 2009](https://marlerclark.com/news_events/case-news?illness=all&year=2009) [Foodborne Illness Lawsuits in 2010](https://marlerclark.com/news_events/case-news?illness=all&year=2010) [Foodborne Illness Lawsuits in 2011](https://marlerclark.com/news_events/case-news?illness=all&year=2011) [Foodborne Illness Lawsuits in 2012](https://marlerclark.com/news_events/case-news?illness=all&year=2012) [Foodborne Illness Lawsuits in 2013](https://marlerclark.com/news_events/case-news?illness=all&year=2013) [Foodborne Illness Lawsuits in 2014](https://marlerclark.com/news_events/case-news?illness=all&year=2014) [Foodborne Illness Lawsuits in 2015](https://marlerclark.com/news_events/case-news?illness=all&year=2015) [Foodborne Illness Lawsuits in 2016](https://marlerclark.com/news_events/case-news?illness=all&year=2016) [Foodborne Illness Lawsuits in 2017](https://marlerclark.com/news_events/case-news?illness=all&year=2017) [Foodborne Illness Lawsuits in 2018](https://marlerclark.com/news_events/case-news?illness=all&year=2018) [Foodborne Illness Lawsuits in 2019](https://marlerclark.com/news_events/case-news?illness=all&year=2019) [Foodborne Illness Lawsuits in 2020](https://marlerclark.com/news_events/case-news?illness=all&year=2020) [Foodborne Illness Lawsuits in 2021](https://marlerclark.com/news_events/case-news?illness=all&year=2021) [Foodborne Illness Lawsuits in 2022](https://marlerclark.com/news_events/case-news?illness=all&year=2022) [Foodborne Illness Lawsuits in 2023](https://marlerclark.com/news_events/case-news?illness=all&year=2023) [Foodborne Illness Lawsuits in 2024](https://marlerclark.com/news_events/case-news?illness=all&year=2024) [Foodborne Illness Lawsuits in 2025](https://marlerclark.com/news_events/case-news?illness=all&year=2025) [Foodborne Illness Lawsuits in 2026](https://marlerclark.com/news_events/case-news?illness=all&year=2026) ##### Get Help #### Affected by an outbreak or recall? 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