(CNN)Here's a look at what you need to know about E. coli outbreaks.
General Information: (from the CDC)
There are many strains of the bacteria Escherichia coli (E. coli). Most strains are harmless and live in the intestines of healthy humans and animals.
Some kinds of E. coli cause disease by producing Shiga toxin. The bacteria that make these toxins are called "Shiga toxin-producing" E. coli (STEC). The most commonly found STEC in the United States is E. coli O157:H7.
The symptoms of STEC infections can include stomach cramps, diarrhea and vomiting. Some infections are mild, but others can be life-threatening.
The CDC estimates that 265,000 STEC infections occur each year in the United States. E. coli O157:H7 causes over 36% of these infections.
E. coli O157:H7 was first recognized in 1982.
People of all ages can be infected, but young children and the elderly are more likely to develop severe symptoms.
The types of E. coli that can cause illness can be transmitted through contaminated water or food, or through contact with animals or people.
To avoid E. coli infections, experts advise to thoroughly cook meat, avoid unpasteurized dairy products and juices, avoid swallowing water while swimming, and wash hands regularly.
1998 - The Hazard Analysis and Critical Control Points program (HACCP) begins requiring meat processors to establish critical checkpoints in the plants to prevent pathogens from contaminating meat.
- Inspectors from the food-safety agency randomly test all facilities that grind meat products to make sure that the plants are complying with the HACCP program.
1999 - The USDA approves the irradiation process for meat. Irradiation is a process that uses beams of high-speed electrons to kill E. coli and other bacteria.
May 2000 - Huisken Meats of Sauk Rapids, Minnesota, becomes the first meat processor to begin selling irradiated ground beef to retailers.
June 2009 - Epitopix LLC, a Minnesota based veterinary pharmaceutical company, begins licensing a new vaccine for cows that reduces the transmission of E. coli between cows and humans.
Timeline of selected severe E. coli O157:H7 cases in the U.S.
Jack in the Box - January 1993
The Jack in the Box outbreak kills three children and makes about 500 people sick in the Northwest United States.
The Jack in the Box incident leads the Clinton administration to begin random testing for E. coli in ground beef.
The meatpacking industry sues the USDA to block the tests. The USDA wins the lawsuit.
Hudson Foods - August 1997
August 12, 1997 - 25 million pounds of meat produced at a Hudson Foods plant in Columbus, Nebraska, is recalled.
15 people become ill as a result of the contamination.
After this recall the plant's largest customer, Burger King, stops buying meat from Hudson Foods and the company closes down.
ConAgra Beef Co. - July 2002
July 19, 2002 - 19 million pounds of meat produced at the ConAgra Beef Co.'s Greeley, Colorado, plant is recalled.
At least 35 people become ill due to this meat contamination and one person dies.
The contaminated meat is shipped to at least 21 states.
Prepackaged Spinach - First occurs in September 2006
September 14, 2006 - The FDA issues a warning to consumers about an E. coli O157:H7 outbreak in multiple states. The warning states, "preliminary epidemiological evidence suggests that bagged fresh spinach may be a possible cause of this outbreak."
Fall 2006 - At least 199 cases of E. coli infection occur in 26 states. Three people die and about 31 develop Hemolytic Uremic Syndrome (HUS), a dangerous complication that can lead to kidney failure.
The outbreak is most severe in Wisconsin, where 49 cases are reported to the FDA, and one death is confirmed.
The source of the outbreak is traced to fresh, bagged spinach from the California-based Natural Selection Foods company, which issues a voluntary recall of its spinach products.
The states and number of people affected are: Arizona (7), California (2), Colorado (1), Connecticut (3), Idaho (4), Illinois (1), Indiana (9), Kentucky (8), Maine (3), Maryland (3), Michigan (4), Minnesota (2), Nebraska (9), Nevada (1), New Mexico (5), New York (11), Ohio (25), Oregon (6), Pennsylvania (9), Tennessee (1), Utah (17), Virginia (2), Washington (3), West Virginia (1), Wisconsin (49), Wyoming (1)
October 2006 - The FDA matches the E. coli strain to one found on a cattle ranch located next to the spinach fields in Salinas Valley.
Taco Bell/Taco John's - First occurs November 29, 2006
November 29, 2006 - An outbreak begins in New Jersey and New York at nine different Taco Bell locations.
December 5, 2006 - Taco Bell announces the removal of green onions from Taco Bell restaurants nationwide in response to preliminary tests suggesting they are the cause of the E. coli outbreak.
November-December 2006 - As many as 67 people in five states are confirmed as having the strain of E. coli bacteria involved in the Taco Bell outbreak.
December 2006 - Kevin Teale of the Iowa Department of Health tells CNN that approximately 40 people have reported symptoms consistent with E. coli and 11 to 15 people have been hospitalized in Iowa.
December 13, 2006 - Green onions are ruled out as the cause of the E. coli outbreak.
Topps Ground Beef Patties - First occurs in July 2007
September 25, 2007 - Topps Meat Company issues a recall of its frozen burgers after six people fall ill and three are hospitalized due to E.coli from Topps burgers.
September 29, 2007 - Topps Meat expands its recall to 21.7 million pounds of ground beef products. The company announces a week later that it is going out of business.
October 26, 2007 - An update is released - 40 cases of E. coli identified. At least 21 people are hospitalized and two developed hemolytic-uremic syndrome (HUS).
Nestle Toll House Cookie Dough
June 19, 2009 - Nestle USA announces a voluntary recall of all its Toll House refrigerated cookie dough after reports of 66 illnesses in 28 states.
September 2, 2009 - Estimates of those affected are increased by health officials to 80 reports of illnesses in 31 states.
JBS Swift Beef Co.
April 2, 2009 - The first case of E. coli is reported to the CDC.
June 13, 2009 - The 23rd and last case of E. coli is reported to the CDC. Of those who contracted E. coli, 12 are hospitalized and two suffer some form of kidney failure.
June 24, 2009 - 41,000 pounds of beef are recalled.
June 28, 2009 - 380,000 pounds of beef are recalled.
October 31, 2009 - AFA Foods recalls more than 500,000 pounds of ground beef after an outbreak of E. coli is linked to the deaths of two people.
National Steak and Poultry
December 24, 2009 - The Food Safety and Inspection Service issues a recall for 248,000 pounds of National Steak and Poultry beef.
January 4, 2010 - 21 people from 16 states report being infected with the outbreak strain of E. coli. Nine are hospitalized and one suffers from kidney failure.
November 5, 2010 - 38 people from five states are sickened from cheese sold at Costco. 15 are hospitalized and one suffers from hemolytic uremic syndrome (HUS), a form of kidney failure.
November 23, 2010 - Bravo Farms recalls all of its cheeses.
June 9, 2014 - CDC says that since May 1, 17 people in five states have been sickened by E. coli after consuming clover sprouts. Of the 15 cases that the CDC has information for, seven required hospitalization.
August 1, 2014 - The CDC says the outbreak appears to be over. In all, 19 people were infected in six states: California (1), Idaho (3), Michigan (1), Montana (2), Utah (1) and Washington (11). No deaths were reported.