Bacteria and Viruses are the most commonly seen pathogens in foods that cause food poisoning

Bacteria and viruses are the most common cause of food poisoning. The symptoms and severity of food poisoning vary, depending on which bacteria or virus has contaminated the food.

The common pathogenic bacteria and viruses that cause the most illnesses, hospitalizations, and deaths in the United States are salmonella, norovirus or norwalk virus, campylobacter, E. coli, Listeria and clostridium perfringens.

Salmonella

Pathogenic bacteria and viruses are most likely causes for food poisoning /Credit: content and photo from foodsafety.gov/

Salmonella, the name of a group of bacteria, is one of the most common causes of food poisoning in the United States. Usually, symptoms last 4-7 days and most people get better without treatment. But, Salmonella can cause more serious illness in older adults, infants, and persons with chronic diseases. Salmonella is killed by cooking and pasteurization.

Sources	Food: Contaminated eggs, poultry, meat, unpasteurized milk or juice, cheese, contaminated raw fruits and vegetables (alfalfa sprouts, melons), spices, and nuts Animals and their environment: Particularly reptiles (snakes, turtles, lizards), amphibians (frogs), birds (baby chicks) and pet food and treats.
Incubation Period	12-72 hours
Symptoms	Diarrhea, fever, abdominal cramps, vomiting
Duration of Illness	4-7 days
What Do I Do?	Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration or if your symptoms are severe, call your doctor. Antibiotics may be necessary if the infection spreads from the intestines to the blood stream.
How Can I Prevent It?	Avoid eating high-risk foods, including raw or lightly cooked eggs, undercooked ground beef or poultry, and unpasteurized milk Keep food properly refrigerated before cooking. Clean hands with soap and warm water before handling food. Clean surfaces before preparing food on them. Separate cooked foods from ready-to-eat foods. Do not use utensils on cooked foods that were previously used on raw foods and do not place cooked foods on plates where raw foods once were unless it has been cleaned thoroughly. Cook foods to a safe internal temperature. Use a meat thermometer to make sure foods are cooked to a safe temperature. Chill foods promptly after serving and when transporting from one place to another. Wash your hand after contact with animals, their food or treats, or their living environment.

Norovirus (Norwalk Virus)

Norovirus is another most common germ that causes food poisoning. Specifically, noroviruses are the pathogens in most cases responsible acute gastroenteritis (infection of the stomach and intestines) in the United States. Norovirus illness spreads easily and is often called stomach flu or viral gastroenteritis,

People who are infected can spread it directly to other people, or can contaminate food or drinks they prepare for other people. The virus can also survive on surfaces that have been contaminated with the virus or be spread through contact with an infected person.

Sources	Produce, shellfish, ready-to-eat foods touched by infected food workers (salads, sandwiches, ice, cookies, fruit), or any other foods contaminated with vomit or feces from an infected person
Incubation Period	12-48 hours
Symptoms	Diarrhea, vomiting, nausea,and stomach pain. Diarrhea tends to be watery and non-bloody. Diarrhea is more common in adults and vomiting is more common in children
Duration of Illness	1-3 days. Among young children, old adults, and hospitalized patients, it can last 4-6 days.
What Do I Do?	Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration, call your doctor.
How Do I Prevent It?	Wash hands frequently with soap and running water for at least 20 seconds, particularly after using the bathroom and before preparing food. If you work in a restaurant or deli, avoid bare-hand contact with ready-to-eat foods. Clean and disinfect surfaces contaminated by vomiting or diarrhea (use a bleach-based household cleaner as directed on the label). Clean and disinfect food preparation equipment and surfaces. If you are ill with diarrhea or vomiting, do not cook, prepare, or serve food for others. Wash fruits and vegetables and cook oysters and other shellfish thoroughly before eating them. Wash clothing or linens soiled by vomit or fecal matter immediately. Remove the items carefully to avoid spreading the virus. Machine wash and dry.

Campylobacter

Campylobacter is one of the most common causes of food poisoning in the United States. The vast majority of cases occur as isolated events, not as part of recognized outbreaks.

Sources	Raw and undercooked poultry, unpasteurized milk, contaminated water.
IncubationPeriod	2-5 days
Symptoms	Diarrhea, cramps, fever, and vomiting; diarrhea may be bloody.
Duration of Illness	2-10 days
What Do I Do?	Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration or if your symptoms are severe, call your doctor. In more severe cases, certain antibiotics can be used and can shorten the duration of symptoms if given early in the illness.
How Do I Prevent It?	Always cook meat, especially poultry, to safe minimum temperatures. Keep raw meat, especially poultry, separate from other foods. Do not drink raw or unpasteurized milk.

E. coli

E. coli is the name of a type of bacteria that lives in your intestines and in the intestines of animals. Although most types of E. coli are harmless, some types are pathogenic and can lead to food poisoning. Note that it is not only the bacteria, but also the toxin the bacteria produce can cause food poisoning. It’s just that we do not talk about the toxin often.

The worst type of E. coli, known as E. coli O157:H7, causes bloody diarrhea and can sometimes cause kidney failure and even death. E. coli O157:H7 makes a toxin called Shiga toxin and is known as a Shiga toxin-producing E. coli(STEC). There are many other types of STEC, and some can make you just as sick as E. coli O157:H7.

One severe complication associated with E. coli infection is hemolytic uremic syndrome (HUS). The infection produces toxic substances that destroy red blood cells, causing kidney injury. HUS can require intensive care, kidney dialysis, and transfusions.

Sources	Contaminated food, especially undercooked ground beef, unpasteurized (raw) milk and juice, soft cheeses made from raw milk, and raw fruits and vegetables (such as sprouts) Contaminated water, including drinking untreated water and swimming in contaminated water Animals and their environment: particularly cows, sheep, and goats. If you don’t wash your hands carefully after touching an animal or its environment, you could get an E. coli infection Feces of infected people
Incubation Period	1-10 days
Symptoms	Severe diarrhea that is often bloody, severe abdominal pain, and vomiting. Usually, little or no fever is present. Symptoms of HUS include decreased urine production, dark or tea-colored urine, and facial pallor.
Duration of Illness	5-10 days. Most people will be better in 6-8 days. If HUS develops, it usually occurs after about 1 week.
What Do I Do?	Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration or if your symptoms are severe (including blood in your stools or severe abdominal pain), call your doctor. Antibiotics should not be used to treat this infection.
How Can I Prevent It?	Avoid eating high-risk foods, especially undercooked ground beef, unpasteurized milk or juice, soft cheeses made from unpasteurized milk, or alfalfa sprouts. Use a food thermometer to make sure that ground beef has reached a safe internal temperature of 160° F. Wash hands before preparing food, after diapering infants, and after contact with cows, sheep, or goats, their food or treats, or their living environment .

Listeria

Listeria is the name of a bacteria found in soil and water and some animals, including poultry and cattle. It can be present in raw milk and foods made from raw milk. It can also live in food processing plants and contaminate a variety of processed meats. When listeria are ingested, the foodborn bacteria can cause food poisoning.

Listeria is unlike many other germs because it can grow even in the cold temperature of the refrigerator. Listeria is killed by cooking and pasteurization.

Sources	Ready-to-eat deli meats and hot dogs Refrigerated pâtés or meat spreads Unpasteurized (raw) milk and dairy products Soft cheese made with unpasteurized milk, such as queso fresco, Feta, Brie, Camembert Refrigerated smoked seafood Raw sprouts
Incubation Period	3-70 days
Symptoms	Fever, stiff neck, confusion, weakness, vomiting, sometimes preceded by diarrhea
Duration of Illness	Days to weeks
Who’s at Risk?	Older adults Pregnant women People with weakened immune systems Organ transplant patients who are receiving drugs to prevent the body from rejecting the organ People with certain diseases, such as: HIV/AIDS or other autoimmune diseases Cancer End-stage renal disease Liver disease Alcoholism Diabetes
What Do I Do?	If you are very ill with fever or stiff neck, consult your doctor immediately. Antibiotics given promptly can cure the infection and, in pregnant women, can prevent infection of the fetus.
How Do I Prevent It?	Do not drink raw (unpasteurized) milk, and do not eat foods that have unpasteurized milk in them. Wash hands, knives, countertops, and cutting boards after handling and preparing uncooked foods. Rinse raw produce thoroughly under running tap water before eating. Keep uncooked meats, poultry, and seafood separate from vegetables, fruits, cooked foods, and ready-to-eat foods. Thoroughly cook raw food from animal sources, such as meat, poultry, or seafood to a safe internal temperature. Wash hands, knives, countertops, and cutting boards after handling and preparing uncooked foods. Consume perishable and ready-to-eat foods as soon as possible. Persons in higher risk groups should heat hot dogs, cold cuts, and deli meats before eating them.

At Risk Populations

Listeriosis, an infection caused by Listeria, can pose major risks for certain populations. Namely, pregnant women, older adults, and individuals with weakened immune systems are at greater risk.

Pregnant Women

Pregnant women are approximately 20 times more likely than other healthy adults to get listeriosis. In pregnant women, it is typically a mild, flu-like illness. In the child, listeriosis can lead to miscarriage, stillbirth, or life-long health problems.

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Older Adults

As adults age, it is normal for their bodies not to work as well as they did when they were younger. Changes in their organs and body systems are expected as they grow older. These changes often make them more susceptible to contracting a foodborne illness such as Listeriosis.

Food Safety for Older Adults
A need-to-know guide for those 65 years of age and older

Other At Risk Populations

A properly functioning immune system works to clear infection and other foreign agents from the body. However, certain conditions including cancer and its treatments, diabetes, HIV/AIDS, and organ or bone marrow transplants can weaken the immune system – making the body more susceptible to many types of infections, including foodborne illness such as Listeriosis.

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Food Safety for People with HIV/AIDS
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Food Safety for Transplant Recipients
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Clostridium perfringens

Clostridium perfringens (C. perfringens) is one of the most common causes of food poisoning in the United States. According to some estimates, this type of bacteria causes nearly a million illnesses each year.

Cooking kills the growing C. perfringens cells that cause food poisoning, but not necessarily the spores that can grow into new cells. If cooked food is not promptly served or refrigerated, the spores can grow and produce new cells. These bacteria thrive between 40-140˚F (the “Danger Zone”). This means that they grow quickly at room temperature, but they cannot grow at refrigerator or freezer temperatures.

C. perfringens infections often occur when foods are prepared in large quantities and are then kept warm for a long time before serving. That’s why outbreaks of these infections are usually linked to institutions (such as hospitals, school cafeterias, prisons, and nursing homes) or events with catered food.

Sources	Beef Poultry Gravies
Incubation Period	6-24 hours
Symptoms	Diarrhea and abdominal cramps (not fever or vomiting)
Duration of Illness	24 hours or less In severe cases, symptoms may last for 1-2 weeks.
Who’s at Risk?	Older adults Infants and young children
What Do I Do?	Drink plenty of fluids and get rest. If you cannot drink enough fluids to prevent dehydration, call your doctor.
How Do I Prevent It?	Thoroughly cook foods, particularly meat, poultry, and gravies, to a safe internal temperature. Use a food thermometer Keep food hot after cooking (at 140˚ F or above) Microwave reheated food thoroughly (to 165˚F or above) Refrigerate perishable foods within two hours (at 40˚F or below) Divide leftovers into shallow containers and refrigerate immediately. Do not let them cool on the counter.