Chipotle has temporarily closed dozens of its restaurants in Washington and Oregon out of an abundance of caution after an E. coli scare.

So what is E. coli exactly?

E coli is a common bacteria found inside people and animals. Most E coli strains are harmless. But certain strains of E coli are harmful and can cause severe illness directly or by producing toxins. You can be infected by swallowing food or water that contain the bacteria. Contamination occurs when food or water comes in contact with stool from infected humans and animals. The foods that have been involved with E coli outbreaks include meat (especially ground beef), sprouts, lettuce, onions, spinach, salami, and unpasteurized milk and juice.

Petting zoos and county fairs are places where people can become easily infected with E coli. This is because live animals and human food are together in one place.

Common symptoms of E coli infection

Symptoms often appear 2 to 5 days after ingestion of the contaminated food or drink. They include:

• Watery or bloody diarrhea
• Severe abdominal cramps
• Nausea and vomiting
• Fever, usually less than 101°F (38.3°C)

Diagnosing E coli infection

A sample of your stool is checked for the presence of E coli. More than one stool sample may be needed.

Treating E coli infection

E coli infection generally gets better without treatment in 8 to10 days. Antibiotic medications are usually not prescribed. Do not take antidiarrheal medication unless your doctor tells you to. It can make theyour illness last longer and decrease your body’s ability to get rid of E coli. While you are recovering, drink plenty of fluids to prevent dehydration.

Call your health care provider if you have:

• No improvement in symptoms after 2 days
• Blood in stool
• Severe vomiting
• Severe abdominal pain
• Signs of dehydration (dry, sticky mouth; decreased urine output; very dark urine)

Preventing E coli infection

Follow these steps to lessen the chances of getting or passing E coli infection:

• Wash your hands with soap and warm water often. Do this before preparing meals, and after going to the bathroom, changing diapers, or handling pets. Teach your child to do the same.
• Cook meats to a safe temperature to kill E coli bacteria that may be present in the meat. Use a food thermometer when cooking. Follow these temperature guidelines:
  • Cook ground meat (beef, veal, pork, lamb) and meat mixtures to at least 160°F (71°C).
  • Cook fresh beef, veal, lamb, and pork (steak, roasts, chops) to at least 145°F (63°C).
  • Cook poultry (including ground turkey and chicken) to an internal temperature of at least 165°F (74°C).
• Wash or peel fruits and vegetables before eating.
• Drink only pasteurized milk, juices, and ciders.
• Use one cutting board just for uncooked meat. Wash cutting boards and utensils with hot water and soap after each use. Clean kitchen counters with hot water and soap after each use.
• Don’t swallow or drink water from pools, lakes, streams, or rivers. When camping, or traveling outside the country, avoid drinking or cooking with water unless you know it’s safe. If you need to drink or cook with water you are not sure of, boil it for at least 60 seconds before using it. Or, bring a portable water filter specially made to remove bacteria. Or, bring special drinking water purification tablets that can kill bacteria in drinking water.
• If you drink well water, have it tested once a year for germs, including E coli.
• When visiting petting zoos or county fairs, bring plenty of hand sanitizer. In addition to using hand-washing facilities, use the hand gel often, especially after touching animals and before and after handling food. Help young children clean their hands well.