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Foodborne Disease
Part Tres
Food Intoxications
• Toxins not destroyed by
cooking.
• Appears more rapidly
than food infections
Bacillus cereus
• Intoxication or toxinmediated
• Spore forming
• Facultative
• Vomiting, diarrhea
Symptoms and Onset Time
• 30 minutes to 6 hours
(vomiting)
• 8-16 hours (diarrhea)
Common Foods
• Rice, potatoes,
• Also meats, milk, vegetables, fish
Pasta
• Made from soybeans,
water and a coagulant, or
curdling agent.
• Coagulating soy milk, and
then pressing the
resulting curds into
blocks.
• High in protein and
calcium
Tofu
• Staple of Asian cuisines
for hundreds of years
• Recently become popular
in Western vegetarian
cooking.
Tofu is…
• low in calories
• contains beneficial amounts of iron (especially important
for women of child bearing age)
• no cholesterol
Depending on the coagulant used in manufacturing, the
tofu may also be high in calcium (important for bone
development and maintenance), and magnesium
(especially important for athletes).
Transmission of Bacillus Cereus
• Improperly stored (cooled,
hot held)
• Allows conversion of
spores to vegetative cells
• Vegetative cells produce
the toxins
• Toxins lead to illness
Prevention
• Cooked and held at
135°F
• Cooled to 41°F (rapidly)
Clostridium perfringens
• Anaerobic, spore-forming
• 24 hour flu
• Toxin-mediated infection
(ingested cells colonize and then produce
a toxin in the intestinal tract)
Symptoms and Onset Time
• Abdominal pain and
diarrhea
• Onset 8 to 22 hours
Common Foods
• Meats (boiled, steamed
stewed, braised or
insufficiently roasted)
• Improperly cooled
• Improperly reheated
• Institutional feeding (school cafeterias, hospitals, nursing
homes, prisons, etc.) where large quantities of food are
prepared several hours before serving.
• The young and elderly are the most frequent victims of
perfringens poisoning.
Transmission
• PHFs temperature
abused
• Improperly cooled
• Improperly reheated
Example
• 10 gallon pot of chili
prepared for next days
lunch (beans, meats,
spices tomato base)
• Cooked to boil
• Vegetative cells die, but
spores may survive
• Chili stored in 10 gallon
pot
• 3 days to cool
Prevention
• Cooked adequately
• Cooled from 135°F to
70°F (2 hours) then
• 70°F to 41°F (4 hours)
• Reheated rapidly to
165°F
• Reheat one time
Cooling Foods Quickly
• Cut large items (roast,
ham or turkey) into
smaller pieces.
• Ice water bath
• Shallow containers
• Do not stack pans
• #1 cause of FBI
Staphylococcus aureus
•
•
•
•
Facultative anaerobic
Foodborne intoxication
Heat stable
Grows on cooked foods
• Do not compete well when other microbes are present.
• Found on human skin, hands, hair, nose and throat.
• Burns, infected cuts, pimples, boils
• Grow in foods with high salt or high sugar and low Aw.
Symptoms and Onset Time
• Severe nausea, acute
abdominal pain, vomiting,
diarrhea
• Onset time: 1 to 6 hours
• Last 1-2 days
Common Foods
• Cooked, RTE foods
(luncheon meat, egg
salad, vegetable salads)
• Ham (high salt)
• Milk and dairy products
Transmission in Foods
• Humans are primary
reservoir
• Hands
• Droplets of saliva
(coughing, sneezing near
food)
• Tasting foods (spoons)
Prevention
•
•
•
•
•
No bare hand contact
Employees with cuts
Handwashing
Reuse “tasting” spoons
Danger zone
People are the prime source of Staph.
• Healthy adults carry
Staph in their noses and
skin.
• Foodhandlers must be
conscious of what they
touch and to wash hands
frequently.
Clostridium botulinum
• Anaerobic, spore-forming
• Foodborne intoxication
• Improperly heated
processed foods
(especially home canned)
• Produces a neurotoxin
• Not heat stable
Symptoms and Onset Time
• Fatigue, headaches,
dizziness
• Inability to swallow
• Respiratory paralysis
• Onset time 12-36 hours
• Several days - year
Common Foods
• Low acid foods (pH 4.6),
inadequately heat
processed, packaged
anaerobically (canned or
vacuum pouch)
• Held in the danger zone
• Sautéed onions, Patty Melt sandwich
(Illinois)
• 28 victims (1 died)
• Louisiana – foiled wrapped baked potato
• Left out overnight
Transmission
Ingestion of food that were not heat processed correctly and
packaged anaerobically.
Canned Foods
– Swollen ends
– Leaks and flawed
seals
– Rust
– Dents
Foodborne Disease
Viruses
What are viruses?
• not a bacterium
• not an independently-living organism
• cannot survive in the absence of a living cell within which
to synthesize copies of itself (replicate).
• Unlike living organisms, cannot reproduce independently
• But like living organisms, can reproduce.
• Has some fundamental information which allows it to
make copies of itself.
• Must be inside a living cell
Even though the smallest viruses are only about onemillionth of an inch long, they live up to their Latin
namesake—poison.
Foodborne Illness Caused by Viruses
• Smaller than bacteria
• Require a living host
• Do not reproduce or grow in
foods
Percentage of Foodborne Illness
Attributable to Known Pathogens
Bacteria
30%
Protozoa
3%
Mead et al., 1999
Viruses
67%
• Usually transferred from one food to another from food
handler or contaminated water supply.
• PHF not needed to support survival
• RTE foods most frequently associated with viral
infection.
• Viruses usually have a tough outer covering.
• Can survive on surfaces for several seconds up to a
couple of days.
Viruses also are more likely to remain dangerous on
hard or non-porous surfaces than if they are on porous
surfaces.
3 Viruses
• Hepatitis A
• Norwalk virus
• Rotavirus
Handwashing is the key!
Hepatitis A
• Viral infection
• Causes a liver disease (infectious)
• Food worker can harbor disease for up to 6 weeks w/o
symptoms
• Food workers are infectious one week before onset of
symptoms
Hepatitis A continues to be one of the most frequently
reported vaccine-preventable diseases in the United
States.
From 1980 through 2001, an average of 25,000 cases
each year were reported to the Centers for Disease
Control and Prevention (CDC)
However…
• Underreporting
• Asymptomatic infections
• Estimated average of 263,000 HAV infections occurred
per year
The 411
• Liver disease caused by the hepatitis A virus.
• Can affect anyone.
• Can occur in situations ranging from isolated cases of
disease to widespread epidemics.
• Good personal hygiene and proper sanitation can help
prevent hepatitis A.
• Vaccines- for long-term prevention of hepatitis A virus
infection in persons 12 months of age and older.
Symptoms and Onset Time
• Fever, nausea, vomiting,
abdominal pain, fatigue
• Swelling of liver, jaundice (yellow
skin)
• Onset time: 15-50 days
• Last several weeks – several
months
Common Foods
• infected food worker
preparing salads
• lunch meats, salad bar
items
• sandwiches, bakery
items.
Raw oysters, clams harvested from polluted
waters.
Raw vegetables irrigated or washed with contaminated
water.
Transmission in Foods
Ingestion of food and water that contains the Hepatitis A
virus.
• …has been traced to
diversed foods (donuts,
strawberry sauce,
sandwiches, salads.
• Virus shed in urine, feces
(poor personal hygiene)
Can lead to liver
damage.
HAV contamination of a food product can occur at any
point during cultivation, harvesting, processing,
distribution, or preparation.
The source of most reported foodborne hepatitis A
outbreaks has been HAV-infected food handlers present
at the point of sale (such as in a restaurant) or who
prepare food for social events (such as a wedding).
A single HAV infected food handler can transmit HAV to
dozens or even hundreds of persons and cause a
substantial economic burden to public health.
In Da’ News…..Transmission during growing,
harvesting, processing, or distribution.
HAV-contaminated frozen strawberries were implicated
as the source of an outbreak involving at least 262
persons in 5 states.
HAV-contaminated shellfish
Factors
Inappropriate or illegal shellfish harvesting near known
sources of sewage.
Inappropriate discharge of sewage from fishing boats or
oil platforms near shellfish beds.
Fecally contaminated water & harvested live shellfish.
Prevention
• Handle foods properly
• Cooked to proper
temperature
• Avoid eating raw seafood
• Wash hands and
fingernails thoroughly
after using the toilet.
Mandating proof of vaccination for food handlers or
offering tax credits for food service operators who
provide hepatitis A vaccine to employees have been
implemented in some areas.
Also need to…
• Encourage ill foodhandlers to seek medical attention and
to stay out of the workplace.
• Exclusion from duties that involve contact with food for at
least 1–2 weeks after the onset of jaundice or until
symptoms resolve is reasonable.
Providing sanitary facilities for field workers and
discouraging the presence of children in areas where
food is harvested reduces the potential for contamination
of food during harvesting or processing.
Chlorinated water or water from a source not likely to
be contaminated by sewage should be used for rinsing
produce or ice used for packing.
However
Other than thorough cooking, no reliable disinfection
method for shellfish exists.
Reducing HAV contamination of foods should be
possible using approaches, such as Hazard Analysis
and Critical Control Point (HACCP) systems.
Haccp
HAZARD ANALYSIS CRITICAL CONTROL POINTS
The Flow of Food
RECEIVING
STORAGE
PREPARING
COOKING
HOT HOLDING
SERVING
COOLING
RE-HEATING
Handwashing is critical
Handwashing 101
Wet Hands
Apply Soap
Rub Hands for 20 sec.
Rinse Well
Dry with Paper Towel
Turn off w/paper towel
Open Door w/towel
Norwalk Virus
• Viral infection
• Viruses of the Norwalk
type are now classified as
noroviruses.
In Da’ News..
• Large outbreaks of gastroenteritis which occurred in
Pennsylvania and Delaware in 1987 were caused by
Norwalk virus.
• A contaminated well was the source of both outbreaks.
In Pennsylvania, the ice was used at a football game and
at a cocktail party in Delaware.
Symptoms and Onset Time
• Nausea, vomiting, diarrhea,
abdominal pain
• Headache, low grade fever
• Onset : 24-48 hours
• 1-3 days
Common Foods
• Sewage contaminated
water
• Shellfish
• Raw clams or oysters
• Food handled by ill food
handlers
Transmission in Foods
Ingestion of food and water that has been
contaminated with feces that contain the Norwalk
virus.
Prevention
•
•
•
•
Potable water
Proper cooking
Proper handling
Avoid raw seafood
Pathogens with Extremely Low
Infectious Dose
 Hepatitis A virus ~ 10 or less viral particles
 Norovirus ~ 10 to 100 viral particles
 EHEC is as low as 10 bacterial cells
 Shigella spp. can be as low as 10 bacterial cells
 S.Typhi is considered low ~ 1000 bacterial cells
Potential Transmission Level Norovirus
Shed in the feces at levels up to 10,000,000 viral
particles per gram of feces.
• One projectile vomiting incident can potentially
contaminate the environment with 30,000,000 viral
particles
• Infectious dose of NoV is estimated from 10-100 viral
particles
Transmission of Norovirus
•
•
•
•
Fecal-Oral Route
Airborne Inhalation
Person-to-Person
Environment-to-Person
Norwalk Virus
• 1st recognized in a
school outbreak in
Norwalk, Ohio. (1968)
• Water was suspected.
Cake frosting and salads, as well as drinking water, have
been implicated as a common source of viral infection in
several outbreaks.
Norwalk and Norwalk-like viruses also are referred to as
"noroviruses." infection symptoms include nausea,
vomiting, diarrhea and abdominal cramps.
NV vs. Duke University & Florida State
Football Teams . . . Norovirus Won
• 9/18/98: Duke Univ.
football team ate turkey
sandwiches prepared by
ill food employee
• 9/19/98: Duke team
players - suddenly ill
during game, w/ vomiting
& diarrhea; continued to
play
NV crossed the line of scrimmage
– Transferred via football &
player’s hands
– 11 FSU players became
sick
• 1st documented case of
person-to-person
transmission of NV at sports
event
• In most people, the illness lasts for about one or two
days. People with norovirus illness are contagious from
the moment they begin feeling sick until at least three
days after they recover.
• Infection can be more severe in young children and
elderly people. Dehydration can occur rapidly and may
require medical treatment or hospitalization.
Rotavirus
• Viral infection
• Rotavirus gastroenteritis
• Lead cause of severe diarrhea among
infants and children.
• When a Rotavirus infects a human being it affects the
cells in the digestive tract causing severe diarrhea.
• Pediatric diarrhea caused by this Rotavirus is directly
responsible for the death of 1 million children around the
world.
• Rotavirus is very easy to catch.
• Large amounts of rotavirus are shed
in the stool.
Remember… viruses
•
•
•
•
Do not multiply in food.
Small infectious dose
Poor personal hygiene
Sewage polluted water
• Need a living cell to reproduce
• Do not require PHF to get around
• Some survive freezing and boiling
GOOD PERSONLAL HYGIENE it
the best prevention against viruses!
The Inn
Check Bb!
Wash Yo’ Hands!!