Handout C

• Foodborne Pathogens and Agents include Bacteria, Viruses, Parasites, Toxins, and Prions
• Foodborne Viruses do not replicate in food or water and their numbers do not increase during processing, transport, or storage
• Streptococcus

  • Gram positive
  • S. pyogenes
  • β-hemolytic (pyogenic streptococci)
• Protozoa parasites and associated illnesses

  • Toxoplasma gondii - Toxoplasmosis causing hydrocephalus and blindness in children
  • Cyclospora cayetanensis - Cyclosporiasis causing watery and explosive diarrhea
  • Cryptosporidium parvum - Cryptosporidiosis causing fever, diarrhea, abdominal pain, and anorexia
• Helminth parasites and associated illnesses

  • Taenia saginata - Beef tapeworm causing Taeniasis
  • Taenia solium - Pork tapeworm causing Taeniasis and Cysticercosis
  • Anisakis simplex - Nematode causing Anisakiasis
• Enterococcus

  • Gram positive
  • Fecal streptococci
  • e.g. E. faecalis and E. faecium
• Food sources for Enterococcus


  • Meat
  • sausage
  • evaporated milk
  • cheese
  • raw and pasteurized milk
• Foodborne Viruses and their associated foods

  • Norovirus - Shellfish, Salad
  • Hepatitis A - Fruits, Vegetable, Clams
  • Hepatitis E - Raw shellfish, Raw or undercooked pork products
  • Rotavirus - Salads, Fruits
• Food sources for Streptococcus

  • Temperature-abused milk
  • ice cream
  • eggs
  • steamed lobster
  • ground ham
  • potato salad
  • egg salad
  • custard
  • rice pudding
  • shrimp salad
• Viral Entry into the Food Supply

  Various contamination sources such as shellfish in fecal-polluted marine water, human sewage pollution, poor personal hygiene in food handlers, aerosolization of vomit, contact with contaminated surfaces
• Streptococcus related illnesses

  • Sore throat and scarlet fever
• Foodborne Viruses are environmentally stable, relatively resistant to heat, disinfection, and pH changes, retain their infectivity over time and within the food matrix, shed in large amounts in feces
• Parasites are eukaryotes including Protozoa and Helminths
• Enterococcus related illness

  • Acute and self-limiting diarrhea
• Taenia saginata


  • Beef tapeworm
  • Taeniasis
  • Raw or undercooked beef
• Creutzfeldt-Jakob disease (CJD)


  • Memory problems
  • Behavior changes
  • Vision problems
  • Poor muscle coordination
  • Progress quickly to dementia
  • Coma
  • Death
• Foodborne Pathogens and Agents

  • Bacteria
  • Viruses
  • Parasites
  • Toxins
  • Prions
• Seafood and Shellfish Poisoning

  • Neurotoxic shellfish poisoning
  • Oysters, mussels, clams, scallops
  • Cymnodinium breve (Brevetoxins)
  • Amnesic shellfish poisoning
  • Mussels
  • Pseudonitzschia pungens (Domoic acid)
  • Ciguatera
  • Reef-associated fish
  • Cambierdiscus toxicus (Ciguetera toxin)
  • Ostroepsis lenticularis (Maitotoxin, Scaritoxin)
• Seafood and Shellfish Poisoning

  • Protist and algae
  • Paralytic shellfish poisoning
  • Mussels, oysters, clams, fish
  • e.g. Alexandrium catenella (Saxitoxin)
  • Diarrheic shellfish poisoning
  • Mussels, scallops, clams, oysters
  • e.g. Dinophysis fortii (Okadaic acid)
• Prions


  • Small proteinaceous infectious agents
  • No nucleic acid
  • Cattle meat and milk
  • Modified form of normal cellular protein (misfolded protein)
• Prion Misfolding

  • PrPSc (Prion Protein Scrapie) – Pathogenic form
  • Protease-resistant
  • Insoluble
  • Amyloid – Insoluble crystalline fibers (Prion aggregates)
• Foodborne Pathogens and Agents

  • Bacteria
  • Viruses
  • Parasites
  • Toxins
  • Prions
• Mycotoxins

  • Fungal secondary metabolites
  • Mycotoxicosis
• Anisakis simplex


  • Helminth
  • Nematode (Roundworm)
  • Anisakiasis (Nonspecific abdominal distress)
  • Raw or undercooked fish
• Characteristics of Prion Diseases

  • Long incubation period (years)
  • Loss of muscle coordination (cerebellum)
  • Dementia (loss of memory, intellect, and poor judgement)
  • Progressive insomnia (marked loss of the slow-way-eye-movement phases)
• Native Form of Prion Protein

  • Mammals, birds, and reptiles
  • Prnp – Gene coding for prion protein
  • Encoded by a single exon of a single copy gene
  • PrPC (Prion Protein Cellular) – Native form
• Toxins

  • Food poisoning
  • Protist, Algae, Fungi
• Taenia solium


  • Pork tapeworm
  • Taeniasis
  • Cysticercosis (larval cyst in the brain, muscle, or other tissues)
  • Raw or undercooked pork