Food borne animal parasites, viruses and food borne biohazards


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Food borne animal parasites, viruses and food borne biohazards

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Food borne animal parasites, viruses and food borne biohazards

  1. 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. 2. Content • Parasites – Protozoan Parasites – Parasitic Worms • Food Born Viruses – Hepatitis A – Rotavirus – Norwalk Virus • Food borne Biohazards – Botulism toxin – Afalatoxin – Ochratoxin
  3. 3. Biohazards (toxins) Parasites Food borne illnesses Viruses Bacteria Chemicals
  4. 4. Parasites
  5. 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)
  6. 6. 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
  7. 7. 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
  8. 8. •Sexually reproduce only within the intestines of members of the cat family (felids) Toxoplasma
  9. 9. 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
  10. 10. 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
  11. 11. • 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
  12. 12. 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
  13. 13. • On occasion, Entamoeba is capable of traveling to the liver
  14. 14. 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
  15. 15. 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
  16. 16. Symptoms of giardiasis • Most common symptoms- Diarrhea, abdominal cramps, gas, and nausea • Chronic infection might lead to dehydration and severe weight loss
  17. 17. 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
  18. 18. Nematoda
  19. 19. 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
  20. 20. • 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
  21. 21. 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
  22. 22. 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
  23. 23. • 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
  24. 24. Trematoda
  25. 25. 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
  26. 26. 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.
  27. 27. 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
  28. 28. Cestoda
  29. 29. 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
  30. 30. • 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
  31. 31. How is it infected ?? • Via dirty hands • Fecally contaminated vegetables • Contaminated water or foods
  32. 32. Symptoms of infection • • • • Altered appetite Abdominal pain Diarrhea Constipation
  33. 33. 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
  34. 34. Food Born Viruses
  35. 35. 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
  36. 36. Major 3 types Hepatitis A Rotavirus Food born viruses Norwalk Virus
  37. 37. 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
  38. 38. – 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
  39. 39. 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
  40. 40. 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
  41. 41. 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
  42. 42. 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
  43. 43. • 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)
  44. 44. 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
  45. 45. Food borne Biohazards
  46. 46. 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
  47. 47. 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
  48. 48. Toxin classification Organism Toxin Bacteria Botulinum toxin, Staphylococcus toxin Fungi Afalatoxin, Mycotoxin, Ochratoxin, Patulin Toxic algae Okadaic acid Natural toxins Histamine, Glycoalcoloids
  49. 49. Toxin characteristics • • • • • • • Non replicative (Most are proteinaceous) Non transmittable (human to human) Nonvolatile Colorless Odorless Tasteless Most are stable at standard conditions
  50. 50. 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
  51. 51. Food sources • • • • Improperly canned foods (>pH 4.6) Smoked salmon, trout Fermented foods (Saeurkraut, pickled vegetables) Foods preserved in oil (Fish) Saeurkraut Canned foods
  52. 52. 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)
  53. 53. Food Sources • • • • • Peanuts and peanut butter Tree nuts such as pecans Corn Wheat Oil seeds such as cottonseed peanut butter
  54. 54. 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
  55. 55. Food Sources • • • • • Soy beans Coffee beans Grapes Peanuts Cereals Coffee beans Grapes
  56. 56. 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
  57. 57. How to control • Follow proper food handling and canning methods • Maintain good hygienic practices • Rules and Regulations
  58. 58. Referenes • tsheets/biotoxins/