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FOODBORN INFECTIONS AND
INTOXICATIONS
Mgr. Dana Hrnčířová
Dpt. of Nutrition
3rd Faculty of Medicine
Charles University in Prague
FOODBORNE INFECTIONS AND
INTOXICATIONS
 wide group of infectious diseases
 spread through contaminated food and water
by contact with vomit or feces
 caused by pathogens and toxins
 more than 250 infectious agents
INFECTIOUS AGENTS
 microorganisms and microbial toxins:
bacteria, bacterial toxins, viruses, fungi, protozoans
 enter the body through the gastrointestinal tract, and often causes
the first symptoms there:
nausea, vomiting, abdominal cramps and diarrhea
 secreted by faeces and urine
TRANSMISSION
 Arthropods and other organisms transmit pathogens to
animals (including humans):
at the end of an incubation period
in the course of an illness
during reconvalescence
 Primary contamination
 Secondary contamination (cross contamination)
FOODBORNE OUTBREAKS
 two or more people get sick from the same food
Size and extent is based on:
 which pathogen or toxin is involved
 how much food is contaminated
 where in the food production chain contamination occurs
 where the food is served
 how many people eat it
FOODBORNE OUTBREAKS
 Sporadic: illnesses that are not part of outbreaks
 Small (local) outbreak
 Regional, statewide outbreak
 Endemic (local limitation)
 Epidemic (local and time limitation)
 Pandemic (without local and time limitation)
THE MOST COMMON FOODBORN ILLNESSES
US
Pathogen
Estimated No
of illnesses
%
Norovirus
5,461,731
58
Salmonella (nontyphoidal)
1,027,561
11
Clostridium perfringens
965,958
10
Campylobacter spp.
845,024
9
Staphylococcus aureus
241,148
3
Subtotal
Source: CDC's 2011 estimates for foodborne illness
91
40,000
35,000
33,594
30,724
30,000
25,492
25,102
25,000
22,713
21,653
21,161
20,000
15,000
8,622
10,000
5,000
0
2001
2004
2006
Salmonellosis
2010
2001
2004
2006
2010
Campylobacteriosis
1000
900
800
700
600
500
400
300
200
100
0
2001 2004 2006 2010
Shigellosis
2001 2004 2006 2010
Listeriosis
2001 2004 2006 2010
Hepatitis A
SALMONELLOSIS
 2 species Salmonella enterica
Salmonella bongori
 intestines of birds, reptiles and mammals
 most important in foodborne disease:
S. enterica subspecies enterica (cca 1500 serotypes)
 serotype Enteritidis abbreviated to S. Enteritidis
 serotype Typhimurium (≠ S. Typhi!)
 serotype Infantis
SALMONELLA - growth and survival
 Growth: 7 - 48 ºC
pH 3.7- 9.5
 Resistant to: drying
low temperatures
survives chill and freezing temperatures
 Facultative anaerob
 Inactivated by: heat above 70 °C (pasteurization, …)
pH below 3,8
disinfection (sanitizers)
SALMONELLA - infective dose
 Infective dose vary widely:
105-106 cells
the young or the elderly: 10 - 100 cells
 Period of infectivity: during illness, reconvalescence
SALMONELLA - transmission
 Salmonellosis - a zoonotic infection
 S. lives in intestines of humans and other animals
- reptiles, chickens, young birds
Feces of infected animals → enviroment (soil, surface water)
↓
Food animals (pigs, polutry) ← feed, infected animals
Fresh produce
Direct contact by hands of an infected food handler
Via food preparation surfaces or equipment
SALMONELLA - occurrence in foods
 Foods of animal origin (meat, poultry, eggs and raw milk)
 Fresh produce
 Cooked ready-to-eat foods (cross contamination)
 Processed food
Examples:
 Confectionery, pastries (custard, egg white coating)
 Cooked ready to eat food containing eggs
 Bologna sausage, tripe sausage, meat loaf, liver paste
SALMONELLOSIS - symptoms
 non-typhoid salmonellae
 incubation period: 12 – 36 hours
 1-7 days
 diarrhea, abdominal pains, nausea, vomiting, chills
 dehydration and headaches
 Susceptible individuals: more severe symptoms
 septicaemia, or chronic conditions (reactive arthritis)
 Salmonella Typhi
 Typhoid fever (≠ typhus - rickettsia)
 vaccination
SALMONELLOSIS - treatment
 Gastroenteric form:
oral fluids
severe diarrhea - rehydration with intravenous fluids
 Typhoid form:
ATB (e.g. ampicillin, chloramphenicol)
SALMONELLOSIS - prevention
 Raw eggs!
 Undercooked poultry and meat!
 Raw or unpasteurized milk
 Produce – washed thoroughly
 Prevent cross-contamination!
 Hand washing
 ….
CAMPYLOBACTERIOSIS
 Bacteria C. jejuni (birds)
C. coli (pigs)
Low resistance to enviroment:
 Microaerophilic (require reduced levels of oxygen) to grow
 Heat sensitive: destroyed at temperatures above 48 °C
 Sensitive to salt: 1 % or more – bactericidal
 Inactivation: pH < 4.0
 Can survive for a short time at refrigeration temperatures!
CAMPYLOBACTERIOSIS
- transmission and sources
 Intestines of warm-blooded animals (esp. birds – poultry)
 Poor hygiene (faecal/oral route)
 Fresh poultry and related products
 Other fresh meats
 Raw milk
 Shellfish
 Salads, …
CAMPYLOBACTERIOSIS
Incubation period: 3 – 5 days
Length of infection: 1-7 days
Infective dose: 103
Symptoms: diarrhea, cramping, abdominal pain, and fever
SHIGELLOSIS
Shigella - a family of bacteria that causes diarrhea in humans
 Shigella sonnei (" Group D" Shigella) over 2/3 of shigellosis
in the US, in CR over 90 % of cases
 Shigella flexneri ("group B" Shigella) almost all the rest
 Other types, e.g. Shigella dysenteriae type 1 – developing
world
SHIGELLOSIS
 highly infective disease, infective dose 200 cells
 incubation period 1-3 days
 duration: 5-7 days
SYMPTOMS:
 diarrhea (distal part of colon) – with mucus and blood
 fever
 stomach cramps
risk of dehydration and perforation of colon
SHIGELLOSIS
 Sources of infection:
infected person (diarrheal stools – poor hygiene)
contaminated food
contaminated water
LISTERIOSIS
 bacteria Listeria monocytogenes syrotype 1/2a, 1/2b and 4b
 grows at chill temperatures
 tolerant of high sodium chloride levels
 grows well in aerobic and anaerobic conditions
 inactivated at temperatures above 70 ºC
Infectious dose:
 healthy persons: 103
LISTERIOSIS
Incubation period: 1 to 90 days (mean 30 days)
SYMPTOMS:
 flu-like symptoms, nausea, vomiting, diarrhea
 meningitis, septicaemia
 Pregnant women: mild flu-like ilness (fever, headache)
 ! infection of the fetus → miscarriage, stillbirth, birth
of an infected infant (meningitis)
 Overall mortality rate: 30 %
LISTERIOSIS - sources of infection
 Row foods (vegetable)
 Cooked foods – post-process contamination
 Processed foods:
soft cheeses
unpasteurized milk
confectionery, pastries
cooked meat products
pâtés, ice cream
smoked and lightly processed fish/seafood products
ESCHERICHIA COLI (VTEC, STEC)
 verocytotoxin producing (Shiga-like toxin-producing ) E. coli
 subset of serotypes: enterohaemorrhagic E. coli (EHEC)
 highly pathogenic
 haemorrhagic colitis, HUS
 outbreaks of severe foodborn disease in many countries (serotype
Escherichia coli O157:H7, Germany 2011- O104:H4)
 Foods derived from cattle (minced beef – Hamburger disease)
 Dairy products derived from raw milk
TOXOPLASMOSIS
protozoan parasite Toxoplazma gondii
 Foodborne transmission (undercooked, contaminated meat)
 Animal-to-human transmission (cat’s feces)
 Mother-to-child transmission
Mothers often without symptoms
Miscarriage, stillborn child
Congenitally infected infants - later in life: mental disability,
potential eye loss
 Incubation period: 5 – 23 days
TOXOPLASMOSIS – life cycle
TAENIASIS
 parasitic infection
 tapeworm species:
Taenia saginata (beef tapeworm) – e. Africa
Taenia solium (pork tapeworm) – India, s. Africa, s. America
Taenia asiatica (Asian tapeworm) – Republic of Korea, China,
Taiwan, Indonesia, Thailand
 raw or undercooked beef or pork!
TAENIASIS - symptoms
 Most people – no / mild symptoms:
abdominal pain, loss of appetite, weight loss, upset stomach
 T. saginata: more symptoms because of the size (up to 10 meters)
 T. solium: cysticercosis
 neurocysticercosis (epileptic seizures)
 eye damage
 in muscles – often asymptomatic
TAENIA – life cycle
TRICHINELA
 parasitic infection
 Roundworms (nematodes), genus Trichinella
 classical agent T. spiralis (worldwide, carnivorous and
omnivorous animals)
 other species
T. pseudospiralis (mammals and birds
worldwide)
T. nativa (Arctic bears)
T. nelsoni (African predators and scavengers)
T. britovi (carnivores of Europe and western Asia)
 Row, undercooked meat!
TRICHINELA - life cycle
VIRAL INFECTIONS
 Hepatitis A, E
 Tick-borne encephalitis
 Norovirus and rotavirus (small children up to 5 yrs)
 Norovirus - Norwalk-like virus (Norwalk, Ohio in 1968)
- extremely infectious enteric virus
- acute viral gastroenteritis
- infected persons, contaminated food/water/ surfaces
HEPATITIS A
 Hepatitis A virus
 Foodborne hepatitis
Transmission:
 direct person-to-person contact via the faecal-oral route
 foodborne transmission
 infected food handler
 foods faecally contaminated (water)
 Long incubation period (aprox. 4 weeks)
 Often asymptomatic (esp. Children – source of the virus!)
 Shellfish, fresh fruits/ vegetable, iced beverages, milk products etc.
 resistant at 70°C for up to 10 mins, inactivated at 85°C for 1 min.
HEPATITIS E
 Foodborne disease
 No chronic infection
 Contaminated water!
 Countries with poor sanitation
 No approved vaccination in US and Europe
Hepatitis A and E
1800
1600
1400
1200
Hepatitis A
1000
Hepatitis E
800
600
400
200
0
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
FOODBORNE INTOXICATIONS
 Intoxication
consumption of toxins produced by bacteria in food
Staphylococcus aureus, Clostridium botulinum,Vibrio parahemoliticus
 Toxin-mediated infection
toxin is produced in the intestine
Clostridium perfringens type A
 Bacillus cereus: two types of toxins
 1. Type A - heat resistent toxin, produced in food (staphylococ-like
symptoms)
 2. Type B - heat labile toxin, produced in GIT (clostridium-like
symptoms)
Staphylococcal intoxication
 Staphylococcus aureus
 heat resistant toxin
 produced in food
 incubation period: 1-6 hours
 Symptoms: nausea, abdominal cramps, vomiting, exhaustion
 Source: people (nose, throat, infected skin wounds, pimples)
 Cream fillings (esp. with eggs), potato and meat salads,
processed meats, minced meats
Clostridium perfringens type A
 heat labile toxin
 produced in the intestine
 incubation period: 10-12 hours
 Symptoms: diarrhea, abdominal cramps, nausea
 holding meats at warm room temperature for several hours or cooling
large pots of meat or gravy too slowly in the refrigerator
Bacillus cereus
 Type A toxin (emetic form)
heat resistant toxin
produced in food
staphylococcus-like symptoms (nausea, vomiting)
incubation period:1-5 hours
cooked pasta, rice
 Type B toxin (diarrheal form)
heat labile toxin
produced in the intestine
clostridium-like symptoms (watery diarrhea, abdominal cramps)
incubation period: 5-16 hours
meat, milk, vegetable
Botulism
 heat labile paralytic neuro-toxin
 produced in food
 incubation period: 12-36 hours
Three main types:
 foodborne botulism (food)
 wound botulism (toxin produced in a wound)
 infant botulism (consumed botulinum spores release toxin in GIT)
 Spores – destroyed at 120 °C for 20 min.
 Toxin – inactivated by boiling for 10 min.
Botulism
Growth of C. botulinum:
 Acidity - inhibited at a pH of 4.6 or lower
 Oxygen – anaerobic organism
 Home-canned and home-cooked food (meat and vegetable)
Symptoms:
 blurred double vision, difficulty in swallowing and speaking
 Paralysis (respiratory muscles, peristalsis, urination)
Botulism
Treatment:
 remove any unabsorbed toxin in GIT
 neutralize the circulating toxin with an antitoxin
 keep a patient breathing by a mechanical respirator as necessary
Recovery – weeks to months
Use of toxin (BOTOX):
 Strabismus
 wrinkles and frown lines
 underarm sweating etc.
THANK YOU FOR YOUR ATTENTION.