Chapter 5 SG for food borne illnesses Flashcards
Salmonella bacteria
(food infection)
Causes: Most common cause of U.S. food-borne illness;
infected food source animals, human feces
Common sources: Poultry and eggs are the foods most
commonly contaminated; contaminated meat, dairy
products, seafood, fresh produce, and cereal have caused
outbreaks
Prevention: killed by heat; thoroughly cook foods likely to
be contaminated
Campylobacter jejuni bacteria
(toxin-mediated infection)
Causes: Leading cause of acute bacterial diarrhea in
developed countries
Common sources: undercooked chicken, unpasteurized
milk, and untreated water
Prevention: grows slowly in cold temperatures and is
killed by heat; carefully store and thoroughly cook foods
Escherichia coli (E. coli) bacteria
(toxin-mediated infection)
Causes: some strains are harmless; others can cause serious
food-borne infection
◦One strain in water contaminated by human or animal feces causes
“travelers’ diarrhea”
◦ E. coli O157:H7 produces a toxin causing abdominal pain, bloody
diarrhea, fatal kidney failure
Common sources: fecal contamination of water or food (for
example, meats and produce)
Prevention: cook foods thoroughly, general sanitation
Listeria monocytogenes bacteria
(food infection)
Causes: flulike symptoms; more serious in high-risk groups
(pregnant women, children, elderly people, with
compromised immunity)
◦ During pregnancy: causes spontaneous abortion and stillbirth, fetal
meningitis and blood infections
Common sources: everywhere in environment
Prevention: survives and grows at refrigerator temperatures
so infects ready-to-eat foods; heat hot dogs and lunchmeats
to steaming point and avoid unpasteurized dairy products
Vibrio vulnificus bacteria
(toxin-mediated infection)
Causes: gastrointestinal upset but can be deadly in people with compromised immune systems
Common sources: grows in warm seawater; in raw or
undercooked shellfish, particularly oysters
Prevention: cook shellfish thoroughly
Staphylococcus aureus bacteria
(food-borne Intoxication)
Causes: bacterial food-borne intoxication; toxin causes
vomiting soon after ingestion
Common sources: live in human nasal passages and
transferred to food through coughing or sneezing; grow on food and produces toxin
Prevention: Thorough heating and rapid cooling of foods
Clostridium perfringens bacteria (cafeteria germ)
(food intoxication)
Causes: food-borne infection and intoxication
Common sources: little oxygen gets to the center of large containers providing growth environment for these bacteria that thrive in low-oxygen environments; form heat-resistant spores (stage of bacterial life remaining dormant until environmental conditions favor growth)
Prevention: store foods in shallow and small containers to reduce risk of growth
Clostridium botulinum bacteria
(food intoxication)
Causes: blocked nerve function, resulting in vomiting,
abdominal pain, double vision, and paralysis leading to
respiratory failure and death; deadliest of all bacterial food toxins
Common sources: in soil, water, and animal intestinal tracts; toxin produced when heat-resistant spores grow in low oxygen, low-acid conditions; found in improperly home canned foods and foods held in large containers
Prevention: thorough heating and rapid cooling of foods
Viruses
Not classified as living or as cells since they cannot reproduce
on their own
Transmitted via the oral-fecal route (i.e., contaminated feces
to the mouth)
travel person-to-person or via a carrier (e.g., flies, water, food)
Cannot multiply in food and are inactivated by cooking
◦ Human viruses reproduce only inside human cells
◦ Viruses turn human cells into virus-producing factories
◦ Viruses that cause human diseases cannot grow and reproduce in foods
- Norovirus
- Norwalk Virus
- Hepatitis A
Norovirus
Group of viruses
Cause: about 50% of all US food-borne gastroenteritis (“stomach
flu”)
Common sources: eating food contaminated with virus or touching
contaminated surface and then putting fingers in mouth; Shellfish
can be contaminated in water polluted with feces
Prevention: cooking destroys noroviruses
Norwalk Virus
Virus attaches to the outside of cells in the intestine
Virus genetic material is introduced to intestinal cell
Cell reproduces (killing gut cell)introducing more
genetic material to healthy intestinal cells
Contaminated shellfish, improper hand washing, raw
sewage
Hepatitis A
Causes: liver inflammation, jaundice, fever, nausea, fatigue, and abdominal pain; can require months of recovery but does not require treatment nor cause permanent liver damage
Common sources: food or water contaminated with feces
Prevention: chlorination of drinking water, cooking food, good sanitation, vaccination
Mold/fungus
Many types grow on foods such as bread, cheese, and fruit
Under certain conditions, molds produce toxins (>250 different
mold toxins)
Cooking and freezing stop mold growth but do not destroy toxins
already produced
If food is moldy, discard it, clean the area where it was stored, and
check neighboring foods to see if they are contaminated
Parasites
Organisms that live at the expense of others
- Some are microscopic single-celled animals; others are worms large enough to be seen with the naked eye
- Prevention: killed by thorough cooking; if raw fish is
consumed, parasitic infections can be avoided by eating fish that has been frozen
Giardia lamblia
Single-celled parasites
Causes: cysts in human and animal feces, directly or via water
Common sources: drinking untreated water from streams contaminated with animal feces; in day-care centers where diapers are changed and hands and surfaces are not thoroughly washed
Prevention: general sanitation; thorough cooking
