One in six adults gets sick by consuming contaminated food or beverages every year, according to the Center for Disease Control and Prevention (CDC).

There are more than 250 foodborne illnesses that have been reported, and they are caused by disease-carrying microbes or pathogens that contaminate food. The symptoms of these different diseases vary, but they often affect the intestinal tract, causing nausea, vomiting, cramping and diarrhea. These illnesses are no walk in the park—they’re exhausting, and can last days, even weeks.

Doctors can predict when a flu will hit, but it’s nearly impossible to anticipate a foodborne illness outbreak. Because of this, it’s hard to know which major foodborne illnesses to be concerned about. The experts at HealthGrove used Foodborne Diseases Active Surveillance Network (FoodNet) data to create foodborne illness incidence charts to see if they could identify any trends in prevalence.

To focus the search, HealthGrove only considered foodborne illnesses that hospitalized more than 100 people in 2014 (most recent data available). Illnesses are ordered by fatality rate, from least to most deadly.

#7. E.coli Non-O157

  • Number of People Infected in 2014: 690
  • Hospitalizations in 2014: 104
  • Deaths in 2014: 0
  • Fatality Rate: 0.00%
  • Last Major Outbreak: May 2014


This foodborne illness is a specific strain of E.coli called O121. Escherichia coli (E. coli) are bacteria that live in animal and human intestines which are typically harmless. However, there are other types of E. coli that are pathogenic and cause diarrhea and illness. In 2014, O121 infected 690 Americans in 2014, causing 104 hospitalizations. The most recent outbreak of the illness in August 2014 caused 19 cases in six different states: California, Idaho, Michigan, Montana, Utah and Washington. The visual shows that the incidence of non-O157 E.coli strains has shot up since 2000.

Almost half of the infected persons were hospitalized during the outbreak (44 percent), but thankfully, there were no deaths. The outbreak was eventually linked to the consumption of Evergreen raw clover sprouts.

#6. Shigella

  • Number of People Infected in 2014: 243
  • Hospitalizations in 2014: 569
  • Deaths in 2014: 2
  • Fatality Rate: 0.07%
  • Last Major Outbreak: May 2014-February 2015


Shigella is a group of bacteria that cause Shigellosis, an infectious disease that causes diarrhea, fever and stomach cramps one to two days after a person’s exposure. Some people are asymptomatic, but still pass the bacteria on to others. When symptoms do appear, they last five to seven days, but it can take several months for the infected person’s bowel habits to return to normal.

According to the CDC, the infection is spread by exposure to trace amounts of contaminated fecal matter. Young children are a high-risk group, because Shigellosis often spreads in schools and childcare settings due to hygiene issues.

The most recent major outbreak of Shigella occurred from May 2014-February 2015. The CDC reported that international travelers brought a multidrug-resistant strain of the bacteria back to the U.S., resulting in 243 new cases in 32 states and Puerto Rico. Because this strain of the bacteria is resistant to ciprofloxacin (Cipro), an antibiotic that combats the infection, the outbreak was hard to contain, and over 500 people were hospitalized. As the visualization shows, there was also a substantial outbreak in 2002.

#5. Campylobacter

  • Number of People Infected in 2014: 6,486
  • Hospitalizations in 2014: 1,080
  • Deaths in 2014: 11
  • Fatality Rate: 0.17%
  • Last Major Outbreak: October 2014


Campylobacter is one of the most common causes of diarrheal illness in America. It is usually associated with eating raw or undercooked poultry or meat, and can cause (sometimes bloody) diarrhea, cramping, fever and abdominal pain. Most cases are sporadic, and not a part of an outbreak, but the last known outbreak was in a Wisconsin high school in October of 2014. More than 22 members of the high school football team became ill after a team dinner, and lab results revealed that bacteria in raw milk they had consumed was to blame.

Since 2000, the prevalence of Campylobacter in the U.S. has hovered around 12 or 13 cases per 100,000. In 2014, 11 Americans died from the illness.

#4. Cryptosporidium

  • Number of People Infected in 2014: 1,175
  • Hospitalizations in 2014: 217
  • Deaths in 2014: 4
  • Fatality Rate: 0.34%
  • Last Major Outbreak: April 1993


Cryptosporidium is a microscopic parasite that cause the disease Cryptosporidiosis (“Crypto” for short). Crypto causes watery diarrhea that often develops into a more serious, even life-threatening illness for weak immune systems. Cancer patients, individuals with AIDS, and transplant patients are especially at risk of this deadly foodborne illness.

Although the last major outbreak was in April 1993, it was a bad one: over 400,000 people were infected by contaminated drinking water in Milwaukee, Wisconsin. Most with strong immune systems were able to fight it, but it is estimated over 100 people died due to the incident. The outbreak resulted in extra precautions in water systems nationwide, so we might have Milwaukee to thank for the lack of outbreak since the 90s.

Even without an outbreak, the disease has taken a toll in the United States. In 2014, more than 1000 people were infected, over 200 were hospitalized and four died due to the illness. The visual shows the fluctuation in incidences of Cryptosporidium in the last two decades: the rate almost tripled between 2003 and 2005, and now sits at 2.44 per 100,000 people.

#3. Salmonella

  • Number of People Infected in 2014: 7,452
  • Hospitalizations in 2014: 2,141
  • Deaths in 2014: 30
  • Fatality Rate: 0.40%
  • Last Major Outbreak: June and July, 2015


Many Americans think of Salmonella as the reason they were warned not to eat raw cookie dough or lick the cake batter bowl as a kid. As it turns out, most Salmonella cases are not a result of dessert: many outbreaks trace back to tomatoes and spinach.

Most people who develop Salmonella experience diarrhea, fever and abdominal cramps within one to three days of infection. While many recover without any treatment, Salmonella is one of the more deadly foodborne illnesses in the U.S.: hospitalizations do happen, especially for the elderly, infants and people with impaired immune systems.

The CDC reports five outbreaks of Salmonella in the U.S. in 2015, but the largest was linked to live poultry in people’s backyard flocks. As it turns out, owning chickens can be risky, and the CDC offers a great deal of advice to backyard flock owners. Thankfully, no deaths were reported from any of the five outbreaks. While Salmonella incidence rates have fluctuated greatly over the years, the illness unfortunately appears to be on the rise. It will be interesting to see whether FDA regulations and factory recalls help to lower these numbers in the next few years.

#2. E.coli O157

  • Number of People Infected in 2014: 445
  • Hospitalizations in 2014: 154
  • Deaths in 2014: 3
  • Fatality Rate: 0.67%
  • Last Major Outbreak: May 2014


The second Escherichia coli strain on this list is E.coli O157. This strain is far more deadly, with a 0.67% fatality rate compared to E.coli O121’s rate of 0.

There was a major outbreak of the disease in May 2014, which resulted in 12 cases in four states. The outbreak was traced back to contaminated ground beef from the Wolverine Packing Company. The beef had been shipped to distributors all over the U.S., which explained the expansion to four separate states. Although nobody died during the outbreak, three people in the U.S. died from this strain in 2014, and over 150 were hospitalized.

#1. Listeria

  • Number of People Infected in 2014: 6,486
  • Hospitalizations in 2014: 108
  • Deaths in 2014: 18
  • Fatality Rate: 15.25%
  • Last Major Outbreak: April 2015


America’s most deadly foodborne illness is Listeriosis, which is caused by a bacteria called Listeria. This life-threatening infection affects mostly elderly, pregnant women, newborns and individuals with weak immune systems. Initial symptoms include fever and muscle aches, which are sometimes followed by diarrhea. Almost everyone diagnosed with Listeria contracts an “invasive” infection, meaning the bacteria has spread outside the gastrointestinal tract. Symptoms include headache, stiff neck, confusion and convulsions.

In pregnant women, Listeria can cause fatigue and aching. In some cases, the infection also leads to miscarriage, stillbirth, life-threatening infection to the newborn or premature delivery.

The last Listeria outbreak in the U.S. was in April 2015, and was linked to Blue Bell Creameries products. Ten cases were reported in four states (Arizona, Kansas, Oklahoma and Texas), resulting in 10 hospitalizations and three deaths. Blue Bell recalled all of its products due to the health risk, and shut down every ice cream plant for comprehensive cleanings.

Thankfully, as shown in the incidence graph, it’s clear that the listeria cases are down significantly from the late 1990s.

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