Mgr. Dana HrnčířováDpt. of Nutrition
3rd Faculty of Medicine
Charles University in Prague
FOODBORN INFECTIONS AND INTOXICATIONS
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 periodin the course of an illnessduring reconvalescence
Primary contaminationSecondary 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 involvedhow much food is contaminatedwhere in the food production chain
contamination occurswhere the food is servedhow 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
PathogenEstimated 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 91Source: CDC's 2011 estimates for foodborne illness
2001 2004 2006 2010 2001 2004 2006 2010
2001 2004 2006 2010 2001 2004 2006 20102001 2004 2006 2010
SALMONELLOSIS2 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
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 - growth and survival
Infective dose vary widely:105-106 cellsthe young or the elderly: 10 - 100 cells
Period of infectivity: during illness, reconvalescence
SALMONELLA - infective dose
Salmonellosis - a zoonotic infectionS. 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 handlerVia food preparation surfaces or equipment
SALMONELLA - transmission
Foods of animal origin (meat, poultry, eggs and raw milk)
Fresh produceCooked ready-to-eat foods (cross contamination)Processed food
Examples:Confectionery, pastries (custard, egg white
coating)Cooked ready to eat food containing eggsBologna sausage, tripe sausage, meat loaf, liver
paste
SALMONELLA - occurrence in foods
non-typhoid salmonellaeincubation period: 12 – 36 hours 1-7 daysdiarrhea, abdominal pains, nausea, vomiting,
chillsdehydration and headaches
Susceptible individuals: more severe symptoms septicaemia, or chronic conditions (reactive
arthritis)
Salmonella TyphiTyphoid fever (≠ typhus - rickettsia)vaccination
SALMONELLOSIS - symptoms
Gastroenteric form: oral fluidssevere diarrhea - rehydration with intravenous fluids
Typhoid form: ATB (e.g. ampicillin, chloramphenicol)
SALMONELLOSIS - treatment
Raw eggs!Undercooked poultry and meat!Raw or unpasteurized milkProduce – washed thoroughlyPrevent cross-contamination!Hand washing….
SALMONELLOSIS - prevention
Bacteria C. jejuni (birds)C. coli (pigs)
Low resistance to enviroment: Microaerophilic (require reduced levels of oxygen) to
growHeat sensitive: destroyed at temperatures above 48 °CSensitive to salt: 1 % or more – bactericidalInactivation: pH < 4.0
Can survive for a short time at refrigeration temperatures!
CAMPYLOBACTERIOSIS
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- transmission and sources
Incubation period: 3 – 5 daysLength of infection: 1-7 daysInfective dose: 103
Symptoms: diarrhea, cramping, abdominal pain, and fever
CAMPYLOBACTERIOSIS
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 daysduration: 5-7 days
SYMPTOMS:diarrhea (distal part of colon) – with mucus
and bloodfeverstomach cramps
risk of dehydration and perforation of colon
SHIGELLOSIS
Sources of infection:infected person (diarrheal stools – poor hygiene)contaminated food contaminated water
SHIGELLOSIS
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, diarrheameningitis, 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
LISTERIOSIS - sources of infection
Row foods (vegetable)Cooked foods – post-process contaminationProcessed foods:
soft cheesesunpasteurized milkconfectionery, pastriescooked 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 pathogenichaemorrhagic colitis, HUSoutbreaks 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
protozoan parasite Toxoplazma gondii
Foodborne transmission (undercooked, contaminated meat)
Animal-to-human transmission (cat’s feces)Mother-to-child transmission
Mothers often without symptomsMiscarriage, stillborn childCongenitally infected infants - later in life: mental disability, potential eye loss
Incubation period: 5 – 23 days
TOXOPLASMOSIS
TOXOPLASMOSIS – life cycle
parasitic infection tapeworm species:
Taenia saginata (beef tapeworm) – e. AfricaTaenia solium (pork tapeworm) – India, s. Africa, s. AmericaTaenia asiatica (Asian tapeworm) – Republic of Korea, China, Taiwan, Indonesia, Thailand
raw or undercooked beef or pork!
TAENIASIS
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: cysticercosisneurocysticercosis (epileptic seizures)eye damagein muscles – often asymptomatic
TAENIASIS - symptoms
TAENIA – life cycle
TRICHINELAparasitic infection Roundworms (nematodes), genus Trichinellaclassical 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
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
VIRAL INFECTIONS
HEPATITIS A
Hepatitis A virus Foodborne hepatitisTransmission:direct person-to-person contact via the faecal-oral routefoodborne 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 diseaseNo chronic infectionContaminated water!Countries with poor sanitationNo approved vaccination in US and Europe
Hepatitis A and E
Intoxicationconsumption of toxins produced by bacteria in foodStaphylococcus aureus, Clostridium botulinum, Vibrio parahemoliticus
Toxin-mediated infectiontoxin is produced in the intestineClostridium perfringens type A
Bacillus cereus: two types of toxins1. Type A - heat resistent toxin, produced in food
(staphylococ-like symptoms)2. Type B - heat labile toxin, produced in GIT
(clostridium-like symptoms)
FOODBORNE INTOXICATIONS
Staphylococcal intoxication
Staphylococcus aureus heat resistant toxinproduced in food incubation period: 1-6 hoursSymptoms: 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
heat labile toxinproduced in the intestine incubation period: 10-12 hoursSymptoms: 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
Clostridium perfringens type A
Type A toxin (emetic form)heat resistant toxinproduced in food staphylococcus-like symptoms (nausea, vomiting)incubation period:1-5 hours cooked pasta, rice
Type B toxin (diarrheal form)heat labile toxinproduced in the intestine clostridium-like symptoms (watery diarrhea, abdominal cramps)
incubation period: 5-16 hoursmeat, milk, vegetable
Bacillus cereus
Botulismheat labile paralytic neuro-toxinproduced 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.
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 GITneutralize the circulating toxin with an antitoxinkeep a patient breathing by a mechanical respirator as necessary
Recovery – weeks to months
Use of toxin (BOTOX):Strabismuswrinkles and frown lines underarm sweating etc.
Botulism
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