Food borne animal parasites, viruses and food borne biohazards

1. Food borne animal
parasites, viruses and food
borne biohazards
Dept. of Food Science &
Technology
Wayamba University of Sri
Lanka
108072
108075
108078
108079

2. Content
• Parasites
– Protozoan Parasites
– Parasitic Worms
• Food Born Viruses
– Hepatitis A
– Rotavirus
– Norwalk Virus
• Food borne Biohazards
– Botulism toxin
– Afalatoxin
– Ochratoxin

3. Biohazards
(toxins)
Parasites
Food borne illnesses
Viruses
Bacteria
Chemicals

4. Parasites

5. Parasites..??
• Organisms that obtain their food from other living
creatures
• Smaller than their food source and this
distinguishes them from predators which also eat
other living things
• Common food borne animal parasites - worms
and protozoa
• Worms include tapeworms (cestodes), flukes
(trematodes) and roundworms (nematodes)

7. 1. Protozoan Parasites
• One-celled organisms but are larger and more
complex than bacteria
• Generally not susceptible to antibiotics that kill
bacteria but there are effective drugs to treat some
(not all) parasitic infections
• Most common types;
– Toxoplasma
– Cryptosporidium
– Entamoeba
– Giardia

8. Toxoplasma
• Toxoplasma gondii
• Obligate, intracellular, parasitic protozoan that
causes toxoplasmosis
• Infection in humans and other warm-blooded
animals can occur
– by consuming raw or undercooked meat containing T.
gondii tissue cysts
– by ingesting water, soil, vegetables, or anything
contaminated with oocysts shed in the feces of an
infected animal
– from a blood transfusion or organ transplant
– transplacental transmission from mother to fetus,
particularly when T. gondii is contracted
during pregnancy

9. •Sexually reproduce only within the intestines of
members of the cat family (felids)
Toxoplasma

10. Risk factors of toxoplasmosis and
preventive methods
• Diminished vision or blindness after birth of
child, more severe effects include
hydrocephalus, convulsions, and calcium deposits in
the brain
• Responsible for the deaths of AIDS patients and
causes encephalitis in many immunosuppressed
• Pregnant women and immunocompromised patients
should avoid the following:
– Raw or undercooked meat or eggs
– Unpasteurized milk, particularly goat's milk
– Contact with cat feces, including changing of cat

11. Cryptosporidium
• Mainly Cryptosporidium parvum
• Cause cryptosporidiosis, a parasitic disease of
the mammalian intestine tract
• Primary symptoms - acute, watery, and nonbloody diarrhoea
• Other symptoms -anorexia, nausea/ vomiting and
abdominal pain
• The diagnosis of C. parvum consists of serological
tests and microscopic evaluation of oocysts in
stools using Kinyoun acid-fast staining

12. • The following groups have an elevated risk of
being exposed to Cryptosporidium:
– People who swim regularly in pools with insufficient
sanitation
– Parents of infected children
– People who take care of other people with
cryptosporidiosis
– People who drink untreated water
– People, including swimmers, who swallow water from
contaminated sources
– People who handle infected cattle
– People who eat contaminated food;
meat, fish, milk, fruits and vegetables

13. Entamoeba
• Entamoeba histolytica
• An anaerobic, cause Amoebiasis
• Transmission of the parasite occurs when a person
ingests food/water that has been contaminated
with infected feces
• Cysts of the parasite are the viable form outside
the host. They can survive weeks in water, soils
and on foods under moist conditions.
• An active Entamoeba infection will cause
abdominal pain, fever, severe diarrhea, vomiting

14. • On occasion, Entamoeba is capable of traveling to
the liver

15. Giardia
• Giardia lamblia
• Single celled, flagellated, microscopic parasite
that can live in the intestines of animals and
people
• Cause giardiasis
• Giardiasis does not spread via the bloodstream,
nor does it spread to other parts of the
GI tract

16. How do people get giardiasis?
• Frequently associated with drinking
contaminated water, but some people might get
infected by consuming uncooked meat also
contaminated with G. lamblia cysts (the
infective stage of the organism)
• By putting anything into mouth that has
touched contaminated surfaces or the stool of a
person or animal with giardiasis
• Foodborne giardiasis can result from the use of
contaminated water for irrigating or washing
fruits and vegetables

17. Symptoms of giardiasis
• Most common symptoms- Diarrhea, abdominal
cramps, gas, and nausea
• Chronic infection might lead to dehydration and
severe weight loss

18. 2. Parasitic Worms
• animals that typically have a long cylindrical tubelike body and no legs
• Various types of worm occupy a small variety
of parasitic niches, living inside the bodies of
other animals.
• There are three types of worms found which act as
parasites.
– Nematoda
– Trmatoda
– Cestoda

19. Nematoda

20. Anisakis and Pseudoterranova
(Sealworm,Codworm)
• Anisakiasis was first recognized as a human
disease about forty years ago
• Found with fish
• Chub mackerel and flying squid in Japan and
pickled anchovies, raw sardines, cold smoked
salmon, raw or pickled herring are some vectors

21. • Other fish, including
whiting, mackerel, pollack, and flounder,may
also contain these parasites with anisakid
larvae
• Varies by season and increases with fish size
Water temperatures and seal populations may
also affect the abundance of these parasites

22. What’s Happened When Larvae
Are Ingested By Human ???
• Humans are an accidental host and these larvae
cannot mature in the human gut. Instead the
worms burrow into the intestinal or stomach wall
and may wander to the liver, lungs or other
tissues, causing
• Gastric disturbances and allergic reactions
larvae found in herrings body cavity

23. Ascaris lumbricoides
• Ascaris lumbricoides is a common intestinal
roundworm parasite infecting an estimated onequarter of the world’s population
• Lack of adequate hygiene could spread egg of this
nematode to people who ingest contaminated
foods and drink water

24. •
What Are The Main Causes of
Ascaris ??
Infected babies become stunts growth and
contributes to diarrheal infections and early
childhood mortality
• Infected adults do not exhibit symptoms
• these worms irritate the intestinal lining and
interfere absorption of fats and protein
• Ascaris causes more severe infections in the liver
or lungs

25. Trematoda

26. Clonorchis/Opisthorchis
(Liver flukes)
• In eastern and southeastern Asia, several related
parasitic worms of the genera Clonorchis and
Opisthorchis lodge in the liver of infected humans
and other animals causing blockage and
hyperplasia of the bile passages

27. The way of contamination occur
• Cats and several other animals are vectors
• Raw fish can spread this liver flukes
• Additionally this will be a issue to some other
countries like USA who are importing fresh water
fishes of Asian countries.

28. What happened after infection ??
• Light infections cause mild symptoms like liver
dysfunction
• Heavier infections result in hepatitis and digestive
disorders.
• According to epidemiological reviews there is
significant association between
– chronic infection
– liver cancer,
– cholangiocarcinoma

29. Cestoda

30. Taenia spp.
• Most familiar worm found in intestine of human
when they re infected
• There are number of species which used several
animals as human, dog, even beares as there hosts

31. • T. solium, in particular, may be present in as many
as 20% of hogs
• Causes debilitating human disease that is difficult
and expensive to treat

33. How is it infected ??
• Via dirty hands
• Fecally contaminated vegetables
• Contaminated water or foods

34. Symptoms of infection
•
•
•
•
Altered appetite
Abdominal pain
Diarrhea
Constipation

35. Problems related with infection
• Cysticercosis
• The most serious consequences occur when the
larvae reach the brain, causing neurocysticercosis
• often triggers
– headaches, seizures, and other neurological
symptoms

36. Food Born
Viruses

37. Characteristics
– Small microorganism
– Parasites that replicate/ propagate themselves
within suitable living host cells
– Do not reproduce in food
– Spread usually result of poor hygiene
– Relatively stable and acid resistant outside host
cells

38. Major 3 types
Hepatitis
A
Rotavirus
Food born
viruses
Norwalk
Virus

39. 1. Hepatitis A virus
• Infection
• Incubation: 10-50 days
• Deceases called as Hepatitis A
Infection in humans occur
– Eat or drink food or water that has been
contaminated by feces containing the hepatitis A
virus (fruits, vegetables, shellfish, ice, and water)
– Contact with the feces or blood of a person who
currently has the disease

40. – A person with hepatitis A does not wash his or
her hands properly after going to the bathroom
and touches other objects or food
– Participate in sexual practices that involve oralanal contact
Virulence Mechanisms:
– Ingest virus through food/water/fomite
– Possibly infects intestinal cells
– Moves to liver
– Does not kill liver cells
– Immune response - T-cell destruction of
infected cells
– Virus excreted in bile, then faces

41. Hepatitis A cont.…
Symptoms: 2 - 6 weeks after being exposed to the
hepatitis A virus
– systemic infection characterized by
gastrointestinal manifestations and liver injury
•
•
•
•
•
Sudden fever
Vomiting
Jaundice
abdominal discomfort and bile in urine (Dark urine)
Fatigue

42. 2. Rotavirus
• Infection
• Incubation: 1-3 days
• Inflammation of the stomach and intestines
Infection in humans occur
– Ingestion of contaminated food or water
– Direct contact with contaminated surfaces and
then putting the hands in the mouth

43. Virulence Mechanisms:
• Infects cells that line the small intestine cells
• Produces enterotoxin
• Induces gastroenteritis
• Severe diarrhea and sometimes death through
gastroenteritis
Symptoms:
– Fever
– Stomach cramps
– vomiting, and diarrhea
– Dehydration

44. 3. Norwalk Virus
• Infection
• Incubation: 12 to 48 hours
• Infection of the stomach and intestines
Transitions:
– Ready to eat foods, molluscs and uncooked
– eating food or drinking liquids that are
contaminated with norovirus,
– Touching surfaces or objects contaminated with
norovirus then putting your fingers in your
mouth, or
– Touched infected workers or any other foods
contaminated with vomit or feces from an
infected person

45. • Symptoms :
– Nausea
– Vomiting (more often children)
– Diarrhea (more often adults)
– Anorexia
– Low grade fever, aches, chills, malaise
• Recovery: 12 to 60 hours usually
• Shedding up to 1 week! (feces, vomit)

46. Virulence Mechanisms:
– Eat or drink food or water that has been
contaminated by feces containing the hepatitis
A virus (fruits, vegetables, shellfish, ice, and
water)
– Contact with the feces or blood of a person
who currently has the disease
– A person with hepatitis A does not wash his or
her hands properly after going to the bathroom
and touches other objects or food
– Participate in sexual practices that involve oralanal contact

47. Food borne
Biohazards

48. Biotoxins
• Biotoxin is a poisonous substance that is a specific
product of the metabolic activities of a living
organism (Plant, animal, bacteria, fungus)
• Cause food intoxications
• Toxicity depends on dose

49. Food Intoxication
• Microbes grow in foods produce toxins
• Toxins are ingested with the food and cause health
problems
• Most heat treatments are effective to kill
microbes, but toxins remain

50. Toxin classification
Organism
Toxin
Bacteria
Botulinum toxin, Staphylococcus
toxin
Fungi
Afalatoxin, Mycotoxin,
Ochratoxin, Patulin
Toxic algae
Okadaic acid
Natural toxins
Histamine, Glycoalcoloids

51. Toxin characteristics
•
•
•
•
•
•
•
Non replicative (Most are proteinaceous)
Non transmittable (human to human)
Nonvolatile
Colorless
Odorless
Tasteless
Most are stable at standard conditions

52. 1. Botulism toxin
• Agent: Chlostridium botulinum
• Toxicity: 1ng/kg
– 500g is enough to kill the human race
• Disturb the acetylecholine mechanism at
neuromuscular junctions
• Symptoms
– Nausea, vomiting, diarrhea, headache, lethargy,
double vision, respiratory stress, death

53. Food sources
•
•
•
•
Improperly canned foods (>pH 4.6)
Smoked salmon, trout
Fermented foods (Saeurkraut, pickled vegetables)
Foods preserved in oil (Fish)
Saeurkraut
Canned foods

54. 2. Afalatoxin
•
•
•
•
Agent: Aspergillus flarus
Afalatoxin B1, B2, G1, G2 (B1 is the most common)
Toxicity: 0.5-10 mg/kg
Liver cancer, chronic hepatitis, jaundice, cirrhosis
(Low levels long time)
• Cause acute toxicity, and potentially death (High
exposure)

55. Food Sources
•
•
•
•
•
Peanuts and peanut butter
Tree nuts such as pecans
Corn
Wheat
Oil seeds such as cottonseed
peanut butter

56. 3. Ochratoxin
•
•
•
•
•
Agent: Aspergillus ochraceus
Toxicity: No documented acute toxicity in humans
Tolerable weekly intake 120ng/kg (EFSA)
Has genotoxic and teratogenic effects
Relatively heat stable

57. Food Sources
•
•
•
•
•
Soy beans
Coffee beans
Grapes
Peanuts
Cereals
Coffee beans
Grapes

59. How to control
• Good agricultural practices to avoid insect
damages and mold infection
• Good storage practices (Store below 100C, control
moisture, control RH)
• Separation of contaminated foods before
processing

60. How to control
• Follow proper food handling and canning
methods
• Maintain good hygienic practices
• Rules and Regulations

61. Referenes
• http://www.foodsafetywatch.org/category/fac
tsheets/biotoxins/