Foodborne illnesses — or food poisoning — are caused by consuming a food or beverage contaminated with a pathogen, such as a bacteria, virus, or parasite.
These illnesses cause a range of uncomfortable digestive symptoms and some may cause more severe symptoms that require hospitalization.
This article explains everything you need to know about foodborne illnesses, including their types, causes, and symptoms.
Foodborne illnesses 101
The Centers for Disease Control and Prevention (CDC) estimates that 48 million people get sick, 128,000 are hospitalized, and 3,000 die from foodborne illnesses each year in the United States (1).
As the name suggests, foodborne illnesses originate from food.
There are more than 250 known pathogens — or disease-causing organisms — that cause foodborne illnesses, which are generally named after the pathogen that cause them (1).
Of these, six spread easily through food and make people sick.
These six pathogens are known as the “Big 6,” and include:
- Hepatitis A
- Shiga toxin-producing Escherichia Coli (STEC)
- Salmonella Typhi
- Salmonella (nontyphoidal)
The symptoms of foodborne illnesses vary but generally include:
- abdominal pain
The duration and severity of the symptoms also vary depending on the foodborne illness.
No person is immune from foodborne illnesses but highly susceptible populations are more likely to develop them and experience severe symptoms or require hospitalization from them.
Highly susceptible populations include:
- people with conditions that weaken the immune system (immunocompromised) like cancer
- preschool-aged children
- older adults
- pregnant women
Foodborne illnesses are caused by pathogens that are transmitted by food. They cause uncomfortable digestive symptoms and susceptible populations are particularly vulnerable to developing them.
Foodborne illnesses A to Z
Here’s an overview of common foodborne pathogens, the illnesses they cause, and the factors that define them (2):
|Foodborne Pathogen (Illness)||Type||Symptom Onset||Symptoms||Symptom Duration||Common Sources|
|Bacteria||10–16 hours||Nausea, stomach cramps, watery diarrhea||24–48 hours||Gravies, meats, stews|
|Bacteria||2–5 days||Diarrhea (may be bloody), nausea, stomach pain, vomiting||2–10 days||Contaminated water, raw and undercooked poultry, unpasteurized milk|
|Bacteria||12–72 hours||Diarrhea, difficulty swallowing, muscle weakness, vomiting||Variable||Baked potatoes in foil, fermented fish, improperly canned foods|
|Bacteria||8–16 hours||Stomach cramps, watery diarrhea||24 hours||Gravies, meats, poultry|
|Bacteria||2–10 days||Diarrhea, fever, stomach cramps||May be reoccurring over several weeks to months||Contaminated water, foods handled by an infected food handler, undercooked food|
|Escherichia coli 0157:H7|
|Bacteria||1–8 days||Diarrhea (often bloody), stomach cramps, vomiting||5–10 days||Contaminated water, raw produce, undercooked beef, unpasteurized milk and juice|
|Bacteria||1–3 days||Diarrhea, stomach cramps, some vomiting||3–7 days||Water or food contaminated with human feces|
|Bacteria||9–48 hours||Diarrhea, fever, flu-like symptoms in pregnant women, nausea||Variable||Deli meats, unpasteurized milk, soft cheese, deli meats|
|Bacteria||1–3 weeks||Achiness, diarrhea, fever, stomach cramps||2–4 weeks||Contaminated produce, poultry, meat, unpasteurized milk or juice|
|Bacteria||6–72 hours||Diarrhea, fever, nausea, stomach cramps||4–7 days||Contaminated produce, poultry, meat, unpasteurized milk or juice|
(Shigellosis or Bacillary dysentery)
|Bacteria||4–7 days||Diarrhea (may be bloody), fever, stomach cramps||24–48 hours||Contaminated water, foods handled by an infected food handler, raw produce, uncooked foods|
|Bacteria||1–6 hours||Diarrhea, nausea, stomach cramps, vomiting||24–48 hours||Cream pastries, potato and egg salads, unrefrigerated or improperly refrigerated meats|
(V. parahaemolyticus or V. vulnificus)
|Bacteria||1–7 days||Diarrhea, fever, nausea, stomach cramps, vomiting||2–8 days||Undercooked or raw seafood|
|Bacteria||4–7 days||Diarrhea, stomach pain||1–3 weeks||Raw or undercooked pork|
|Virus||15–50 days||Dark urine, diarrhea, flu-like symptoms, jaundice, stomach pain||2–12 weeks||Contact with an infected food handler, raw produce, shellfish from contaminated water|
(Gastroenteritis or food poisoning)
|Virus||12–48 hours||Diarrhea, stomach cramps, nausea, vomiting||12–60 hours||Foods handled by an infected food handler, raw produce, shellfish from contaminated waters|
|Parasite||7 days||Bloating, diarrhea, nausea, stomach cramps||May be recurring over several weeks to months||Baby lettuce, basil, raspberries|
|Parasite||1–2 weeks||Diarrhea, stomach cramps, nausea||2–6 weeks||Foods handled by an infected food handler, contaminated water|
|Parasite||3–14 days||Chills, difficulty breathing, fever, muscle pain||5–45 days||Raw or undercooked pork|
There are many foodborne illnesses. Most foodborne illnesses share similar symptoms but differ in symptom onset, duration, and severity.
How foodborne illnesses occur and spread
Arising from food hazards, there are several ways that foodborne illnesses occur and spread.
Some of the most common ways include:
- purchasing food from unsafe sources
- failing to cook food adequately
- holding food at improper temperatures
- using contaminated equipment
- poor personal hygiene
Purchasing food from unsafe sources
The contamination of food with pathogens can occur at any step throughout the supply chain, including the environment where animals are raised and plants are grown and harvested, and during processing, packaging, and handling.
Preventing contamination isn’t always possible, but purchasing food from reputable suppliers that are inspected and meet all local, state, and federal food safety laws reduces this risk.
Failing to cook food adequately
Heat is able to destroy most of the bacteria and parasites that cause foodborne illnesses.
For this reason, foods have a minimum internal temperature that they must meet to kill these pathogens.
For example, poultry must be cooked to a minimum internal temperature of 165ºF (74ºC) while ground meats must be cooked to at least 155ºF (68ºC) for 17 seconds to kill off pathogens.
Undercooking foods allow these pathogens to survive which can then make you sick.
Holding food at improper temperatures
Bacteria multiply rapidly when food is between 41ºF (5ºC) and 135ºF (57ºC).
This range is known as the temperature danger zone.
Anytime that cold food is held above 41ºF (5ºC) or hot food is held below 135ºF (57ºC), the risk of bacteria growing to harmful levels increases significantly.
This is why you must hold hot at 135ºF (57ºC) or higher and cold foods at 41ºF (5ºC) or lower to keep them safe.
Foods that require time and temperature controls are known as TCS foods.
Using contaminated equipment
Cross-contamination can spread pathogens easily during food preparation.
Cross-contamination occurs when harmful bacteria are accidentally transferred from one food to the next.
It usually occurs when a food handler works with raw meats, poultry, or seafood and then switches to handling ready-to-eat (RTE) foods like cooked hot dogs, washed fruits or vegetables, salads, or sandwiches.
Cross-contamination can occur due to improper handwashing, touching food with your bare hands, or using the same equipment, utensils, or food preparation surface.
Poor personal hygiene
However, most food handlers don’t wash their hands correctly or when they’re supposed to, promoting the spread of pathogens.
Pathogens can get onto your hands after using the toilet or handling food that contains them.
Many people also carry pathogens like Staphylococcus aureus in their nasal cavities or on their skin.
Read more about good personal hygiene practices for food handlers.
Purchasing foods from unsafe sources, failing to cook foods adequately, and holding foods at improper temperatures are common ways foodborne illnesses occur and spread. Using contaminated equipment and poor personal hygiene are also common reasons.
Preventing foodborne illnesses
Preventing foodborne illnesses from occurring and spreading is everyone’s responsibility.
Here are some key ways to do just that:
- wash your hands correctly and often
- wash fruits and vegetables
- cook food to the proper internal temperature
- limit the time food spends in the temperature danger zone
- avoid cross-contamination
- cool foods using the two-stage cooling method
- store foods at the proper temperature
- avoid bare hand contact with preparing or serving RTE foods
- throw leftovers out after seven days
- properly wash, rinse, and sanitize food equipment and dishware in a 3-compartment sink
Understanding how foodborne illnesses occur and spread is key to preventing them.
The bottom line
Foodborne illnesses are caused by consuming a food or beverage contaminated by a pathogen, such as bacteria, virus, or parasite.
They cause digestive symptoms like diarrhea, vomiting, and nausea, and can be particularly harmful to susceptible populations like older adults and others with a weakened immune system.
Several factors contribute to their occurrence and spread, including purchasing food from unsafe sources, failing to cook food adequately, holding food at improper temperatures, using contaminated equipment, and poor personal hygiene.
You can prevent foodborne illness from occurring and spreading by washing your hands correctly and often, cooking food to the proper internal temperature, and storing foods correctly and at the right temperature, among other ways.
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