Foodborne Bacterial Infections ◾ 355
cases turns to bloody diarrhea), and vomiting. Fever may or may not be an associated symptom.
Damage to the lining of the large intestine causes bleeding. Toxins also cause breakdown of red
blood cells and clotting in the small blood vessels of the kidney, causing kidney damage and occasional kidney failure, causing HUS. It can be fatal, particularly in children. TTP results from a
blood clot in the brain with seizures, coma, and often death.
Food Association
The pathogen is generally present in the intestine of animals, particularly in cattle, without producing
symptoms. 26,27 Stx-producing Esc. coli (STEC) has been also isolated from the feces of chicken, goats,
sheep, pigs, dogs, cats, and seagulls. Food of animal origin, especially ground beef, has been implicated
in many outbreaks in the United States, Europe, and Canada. Irrigation water and soils are the major
risk factors for STEC transmission. Beef cattle operation can contaminate irrigation water, or untreated
manures can directly contaminate produce. In 2006, a major outbreak involving multiple states was
associated with spinach, and the contamination source was attributed to the nearby beef cattle operation. The affected people were found to have consumed spinach and lettuce in salad or improperly
cooked, contaminated hamburgers. Since then, numerous fresh produce–related outbreaks were associated with STEC. 28 In a 1993 outbreak, affecting over 500 people and causing four deaths, consumption of hamburgers served by a fast-food chain in Washington, Nevada, Oregon, and California was
implicated. The hamburgers, contaminated with Esc. coli O157:H7, were cooked at a temperature that
failed to kill the pathogen. In addition to ground beef, other foods, such as raw milk, mayonnaise, apple
cider, some fruits, uncooked sausages, fermented hard salami, sprouts, and salad have been implicated.
Investigations revealed the presence of Esc. coli O157:H7 in many different types of foods of animal
origin, such as ground beef, pork, poultry, lamb, and raw milk, in low percentages. The organism was
isolated in low frequencies from dairy cows as well as calves and chickens.
Prevention
Proper sanitation, cooking or heating at appropriate temperatures, proper refrigeration, and prevention of cross-contamination should be practiced in order to control the presence of Esc. coli
O157:H7 in a ready-to-eat food. The Food Safety Inspection Service (FSIS) in the United States
has provided the following guidelines to control foodborne illness from this pathogen: Use only
pasteurized milk; quickly refrigerate or freeze perishable foods; never thaw a food at room temperature or keep a refrigerated food at room temperature over two hours; wash hands, utensils,
and work areas with hot soapy water after contact with raw meat and meat patties; cook meat or
patties until the center is gray or brown; and prevent fecal-oral contamination through proper personal hygiene. Because fresh produce is becoming the major source of many foodborne pathogens,
including STEC, efforts are made to decontaminate produce surfaces using liquid (hypochlorite
solution, hydrogen peroxide) or gaseous (ozone, chlorine dioxide gas) sanitizers.
Shigella Species 22
Importance
The genus Shigella contains four species: Shigella dysenteriae, Shi. flexneri, Shi. boydii, and Shi.
sonnei, and each species has several serovars. Shi. dysenteriae is responsible for a brisk but deadly
cases turns to bloody diarrhea), and vomiting. Fever may or may not be an associated symptom.
Damage to the lining of the large intestine causes bleeding. Toxins also cause breakdown of red
blood cells and clotting in the small blood vessels of the kidney, causing kidney damage and occasional kidney failure, causing HUS. It can be fatal, particularly in children. TTP results from a
blood clot in the brain with seizures, coma, and often death.
Food Association
The pathogen is generally present in the intestine of animals, particularly in cattle, without producing
symptoms. 26,27 Stx-producing Esc. coli (STEC) has been also isolated from the feces of chicken, goats,
sheep, pigs, dogs, cats, and seagulls. Food of animal origin, especially ground beef, has been implicated
in many outbreaks in the United States, Europe, and Canada. Irrigation water and soils are the major
risk factors for STEC transmission. Beef cattle operation can contaminate irrigation water, or untreated
manures can directly contaminate produce. In 2006, a major outbreak involving multiple states was
associated with spinach, and the contamination source was attributed to the nearby beef cattle operation. The affected people were found to have consumed spinach and lettuce in salad or improperly
cooked, contaminated hamburgers. Since then, numerous fresh produce–related outbreaks were associated with STEC. 28 In a 1993 outbreak, affecting over 500 people and causing four deaths, consumption of hamburgers served by a fast-food chain in Washington, Nevada, Oregon, and California was
implicated. The hamburgers, contaminated with Esc. coli O157:H7, were cooked at a temperature that
failed to kill the pathogen. In addition to ground beef, other foods, such as raw milk, mayonnaise, apple
cider, some fruits, uncooked sausages, fermented hard salami, sprouts, and salad have been implicated.
Investigations revealed the presence of Esc. coli O157:H7 in many different types of foods of animal
origin, such as ground beef, pork, poultry, lamb, and raw milk, in low percentages. The organism was
isolated in low frequencies from dairy cows as well as calves and chickens.
Prevention
Proper sanitation, cooking or heating at appropriate temperatures, proper refrigeration, and prevention of cross-contamination should be practiced in order to control the presence of Esc. coli
O157:H7 in a ready-to-eat food. The Food Safety Inspection Service (FSIS) in the United States
has provided the following guidelines to control foodborne illness from this pathogen: Use only
pasteurized milk; quickly refrigerate or freeze perishable foods; never thaw a food at room temperature or keep a refrigerated food at room temperature over two hours; wash hands, utensils,
and work areas with hot soapy water after contact with raw meat and meat patties; cook meat or
patties until the center is gray or brown; and prevent fecal-oral contamination through proper personal hygiene. Because fresh produce is becoming the major source of many foodborne pathogens,
including STEC, efforts are made to decontaminate produce surfaces using liquid (hypochlorite
solution, hydrogen peroxide) or gaseous (ozone, chlorine dioxide gas) sanitizers.
Shigella Species 22
Importance
The genus Shigella contains four species: Shigella dysenteriae, Shi. flexneri, Shi. boydii, and Shi.
sonnei, and each species has several serovars. Shi. dysenteriae is responsible for a brisk but deadly