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E. coli, listeria, and salmonella outbreaks: symptoms and definitions

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E. coli, listeria and salmonella bacteria are once again making headlines and making Americans sick. But what exactly are these little troublemakers?

Honestly, unless you have a microscope and bacterial samples (and some knowledge of microbiology), it can be difficult to tell the difference between them.

But health experts carefully track outbreaks of both diseases to limit the damage. In recent months, authorities say dozens of people have become ill with E. coli from eating McDonald's Quarter Pounders, and one person has died; 59 people were hospitalized and 10 died in a listeria outbreak linked to sliced ​​deli meat; and 93 people in about a dozen states have been infected with salmonella from eggs.

It's important to note that while food recalls and safety warnings are concerning, they are not uncommon. They can be viewed on the Food and Drug Administration list.

Here's what you should know about the bacteria behind these recent food recalls:

What you should know about bacteria

E.coli: There are several types of Escherichia coli, or E. coli, that are found in food and water and in the intestines of people and animals, according to the U.S. Centers for Disease Control and Prevention. Transmission often occurs through food or water contaminated by human or animal feces.

Certain types of E. coli can cause different body reactions. Some forms can make you sick. Shiga toxin-producing infection is the most common E. coli disease.

Listeria: Listeria makes people sick through food and is the third leading cause of death from foodborne illness in the United States, according to the CDC.

The bacterium is unique because it thrives in cool, moist environments, the U.S. Department of Agriculture said. Listeria can grow in the refrigerator.

Salmonella: Salmonella causes the most common deaths from foodborne illnesses.

Salmonella lives in the intestines of humans and animals. Fewer than 100 of the more than 2,500 species of Salmonella bacteria cause illness. Illnesses are caused by eating contaminated food, drinking or contact with water, and touching feces, animals or their habitats.

What are the symptoms?

E.coli: Symptoms typically begin three to four days after consuming contaminated food or water. The Shiga toxin-producing form of E. coli, the strain identified in the McDonald's outbreak, causes severe stomach cramps, often bloody diarrhea and vomiting. People can develop serious kidney problems that require hospitalization.

Listeria: There are two types of diseases: intestinal and invasive.

According to the CDC, intestinal disease is harder to diagnose because labs don't regularly test for listeria. Symptoms – such as diarrhea and vomiting – usually begin within a day of eating food contaminated with listeria and usually last up to three days.

Intestinal symptoms are usually mild, but some develop an invasive form that spreads beyond the intestines. Symptoms begin about two weeks after eating food contaminated with listeria.

People who are not pregnant can expect fever, muscle aches and fatigue that feels like the flu, headaches, stiff neck, confusion, loss of balance, and seizures. About one in six people dies from invasive listeria disease.

Pregnant women may experience fever and flu-like symptoms such as muscle aches and fatigue. Symptoms are typically mild, but invasive disease during pregnancy usually results in miscarriage, stillbirth, premature birth or a life-threatening infection of the newborn, the CDC says.

Salmonella: According to the CDC, symptoms usually begin between six hours and six days after consuming bacteria. Most sufferers experience stomach cramps and watery diarrhea that may contain blood or mucus, and some may experience headaches, nausea, vomiting and loss of appetite. Without treatment, they usually recover in four to seven days.

However, some are at higher risk of serious illness requiring medical treatment or hospitalization. This includes children under 5 years old, older people aged 65 and over and people with weakened immune systems.

Call a doctor if diarrhea or vomiting persists for more than two days, bloody stools or urine, fever over 102 degrees, signs of dehydration, and long-term complications.

How to prevent foodborne illnesses

Consumers can take simple steps to reduce the risk of illness. First, check for food safety warnings and recalls.

Washing your hands regularly with warm soap and water before and after preparing food or after touching an animal or contaminated items such as diapers is a simple way to reduce the risk of illness, according to the USDA. Clean and disinfect items or surfaces that have come into contact with raw food or waste. Additionally, avoid cross-contamination of food or surfaces.

According to the CDC, salmonella grows in warmer conditions. Refrigerate or freeze perishable foods, prepared foods and leftovers within two hours or sooner if it is hot outside.

According to the FDA, listeria thrives in refrigerators. The temperature in refrigerators should be 40 degrees or below, in freezers 0 degrees. Also, be sure to use ready-to-eat, refrigerated foods before the best-before date listed on the package, as the longer they are kept in the refrigerator, the more chance Listeria has to grow. Also clean refrigerators regularly.