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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